Lindsay Hecox v. Bradley Little

Opinion

FOR PUBLICATION FILED UNITED STATES COURT OF APPEALS JUN 7 2024 MOLLY C. DWYER, CLERK U.S. COURT OF APPEALS FOR THE NINTH CIRCUIT

LINDSAY HECOX; JANE DOE, with her No. 20-35813 next friends Jean Doe and John Doe, D.C. No. 1:20-cv-00184-DCN Plaintiffs-Appellees,

v. AMENDED OPINION

BRADLEY LITTLE, in his official capacity as Governor of the State of Idaho; SHERRI YBARRA, in her official capacity as the Superintendent of Public Instruction of the State of Idaho and as a member of the Idaho State Board of Education; INDIVIDUAL MEMBERS OF THE STATE BOARD OF EDUCATION, in their official capacities; BOISE STATE UNIVERSITY; MARLENE TROMP, in her official capacity as President of Boise State University; INDEPENDENT SCHOOL DISTRICT OF BOISE CITY, # 1; COBY DENNIS, in his official capacity as superintendent of the Independent School District of Boise City #1; INDIVIDUAL MEMBERS OF THE BOARD OF TRUSTEES OF THE INDEPENDENT SCHOOL DISTRICT OF BOISE CITY, # 1; in their official capacities; INDIVIDUAL MEMBERS OF THE IDAHO CODE COMMISSION, in their official capacities,

Defendants-Appellants,

and MADISON KENYON; MARY MARSHALL,

Intervenors.

LINDSAY HECOX; JANE DOE, with her No. 20-35815 next friends Jean Doe and John Doe, D.C. No. 1:20-cv-00184-DCN Plaintiffs-Appellees,

v.

BRADLEY LITTLE, in his official capacity as Governor of the State of Idaho; SHERRI YBARRA, in her official capacity as the Superintendent of Public Instruction of the State of Idaho and as a member of the Idaho State Board of Education; INDIVIDUAL MEMBERS OF THE STATE BOARD OF EDUCATION, in their official capacities; BOISE STATE UNIVERSITY; MARLENE TROMP, in her official capacity as President of Boise State University; INDEPENDENT SCHOOL DISTRICT OF BOISE CITY, # 1; COBY DENNIS, in his official capacity as superintendent of the Independent School District of Boise City #1; INDIVIDUAL MEMBERS OF THE BOARD OF TRUSTEES OF THE INDEPENDENT SCHOOL DISTRICT OF BOISE CITY, # 1; in their official capacities; INDIVIDUAL MEMBERS OF THE IDAHO CODE COMMISSION, in their official capacities,

Defendants,

and

MADISON KENYON; MARY

2 MARSHALL,

Intervenors-Appellants.

Appeal from the United States District Court for the District of Idaho David C. Nye, Chief District Judge, Presiding

Argued and Submitted November 22, 2022 San Francisco, California Opinion Filed August 17, 2023 Opinion Withdrawn April 29, 2024 Amended Opinion Filed June 7, 2024

Before: Kim McLane Wardlaw, Ronald M. Gould, and Morgan Christen, Circuit Judges.**

Opinion by Judge Wardlaw

WARDLAW, Circuit Judge:

In March 2020, Idaho enacted the Fairness in Women’s Sports Act, Idaho

Code §§ 33-6201⁠–06 (2020) (the “Act”), a first-of-its-kind categorical ban on the

participation of transgender women and girls in women’s student athletics. At the

time, Idaho had no history of transgender women and girls participating in

competitive student athletics, even though Idaho’s interscholastic athletics

organization allowed transgender girls to compete on female athletic teams under

certain specified conditions. Elite athletic regulatory bodies, including the

** Pursuant to General Order 3.2(h), Judge Christen has been drawn to replace Judge Kleinfeld in this matter. Judge Christen has reviewed the briefs and the record, and listened to the recording of the oral argument in this case.

3 National Collegiate Athletic Association (NCAA) and the International Olympic

Committee (IOC), also had policies allowing transgender women athletes to

compete if they met certain criteria. The Act, however, bars all transgender girls

and women from participating in, or even trying out for, public school female

sports teams at every age, from primary school through college, and at every level

of competition, from intramural to elite teams. See Idaho Code § 33-6203(1)–(2).

The Act also provides a sex dispute verification process whereby any individual

can “dispute” the sex of any student athlete participating in female athletics in the

State of Idaho and require her to undergo intrusive medical procedures to verify

her sex, including gynecological exams. See Idaho Code § 33-6203(3). Student

athletes who participate in male sports are not subject to a similar dispute process.

Today, we decide only the question of whether the federal district court for

the District of Idaho abused its discretion in August 2020 when it preliminarily

enjoined the Act, holding that it likely violated the Equal Protection Clause of the

Fourteenth Amendment. Because the Act subjects only students who wish to

participate in female athletic competitions to an intrusive sex verification process

and categorically bans transgender girls and women at all levels from competing

on “female[], women, or girls” teams, Idaho Code § 33-6203(2), and because the

State of Idaho failed to adduce any evidence demonstrating that the Act is

substantially related to its asserted interests in sex equality and opportunity for

4 women athletes, we affirm the district court’s grant of preliminary injunctive relief

to Lindsay Hecox. We remand this case to the district court to reconsider the

appropriate scope of injunctive relief in light of the Supreme Court’s decision in

Labrador v. Poe, 144 S. Ct. 921 (2024).

I. FACTUAL AND PROCEDURAL BACKGROUND

A.

As the district court noted, and as we recognize in this context, “such

seemingly familiar terms as ‘sex’ and ‘gender’ can be misleading.” Hecox v. Little

(Hecox I), 479 F. Supp. 3d 930, 945 (D. Idaho 2020) (quoting Doe ex rel. Doe v.

Boyertown Area Sch. Dist., 897 F.3d 518, 522 (3d Cir. 2018)). We therefore adopt

the terminology that has been employed throughout this case.

“Gender identity” is “the term used to describe a person’s sense of being

male, female, neither, or some combination of both.”1 A person’s “sex” is

typically assigned at birth based on an infant’s external genitalia, though “external

genitalia” do not always align with other sex-related characteristics, which include

“internal reproductive organs, gender identity, chromosomes, and secondary sex

characteristics.” A “transgender” individual’s gender identity does not correspond

to their sex assigned at birth, while a “cisgender” individual’s gender identity

1 Joshua D. Safer & Vin Tangpricha, Care of Transgender Persons, 381 N. Eng. J. Med. 2451, 2451 (2019).

5 corresponds with the sex assigned to them at birth. Around two percent of the

population are born “intersex,” which is an umbrella term for people “born with

unique variations in certain physiological characteristics associated with sex, such

as chromosomes, genitals, internal organs like testes or ovaries, secondary sex

characteristics, or hormone production or response.” Id. at 946 (internal quotation

marks omitted).

Over 1.6 million adults and youth identify as transgender in the United

States, or roughly 0.6 percent of Americans who are 13 years old or older.2 Youth

ages 13 to 17 are significantly more likely to identify as transgender, with the

Centers for Disease Control (CDC) estimating that roughly 1.8 percent of high

school students identify as transgender. See Br. of Amici Curiae Am. Acad. of

Pediatrics, et al. (“AAP Br.”) at 10.

Transgender individuals often experience “gender dysphoria,” which is

defined by the Fifth Edition, Text Revision, of the Diagnostic and Statistics

Manual of Mental Disorders (DSM-5-TR) as a condition where patients experience

“[a] marked incongruence between one’s experienced/expressed gender and

assigned gender, of at least 6 months’ duration” that “is associated with clinically

significant distress or impairment in social, occupation, or other important areas of

2 See Jody L. Herman, Andrew R. Flores, Kathryn K. O’Neill, How Many Adults and Youth Identify as Transgender in the United States?, Williams Inst. 1 (2022).

6 functioning.”3 For over thirty years, medical professionals have treated individuals

experiencing gender dysphoria following the protocols laid out in the Standards of

Care for the Health of Transsexual, Transgender, and Gender Nonconforming

People (Version 7), which were developed by the World Professional Association

for Transgender Health (WPATH). AAP Br. at 19.

B.

On March 16, 2020, Idaho passed House Bill 500 (“H.B. 500”), a categorical

ban against transgender women and girls’ participation in any public-school

funded women’s sports, enforced by subjecting all participants in female athletics

to an intrusive sex verification process if their gender is disputed by anyone. See

H.R. 500, 65th Leg., 2d Reg. Sess. (Idaho 2020). Although Idaho was the first

state in the nation to issue such a ban, more than twenty other states have enacted

similar—though perhaps not as potentially intrusive against all female athletes—

restrictions on female transgender athletes.4

3 See Am. Psychiatric Ass’n, Diagnostic and Statistics Manual of Mental Disorders 512–13 (5th ed., text rev. 2022). 4 Since the Act’s passage, twenty-four other states have passed laws or regulations limiting the participation of transgender students in women’s athletics. However, no other state appears to have enacted an enforcement mechanism for those restrictions like the sex dispute verification process in the Act. See Ala. Code § 16-1-52 (2021); 4 Alaska Admin. Code § 06.115(b)(5)(D); Ariz. Rev. Stat. Ann. § 15-120.02 (2022); Ark. Code Ann. § 6-1-107 (West 2021); Fla. Stat. Ann. § 1006.205 (West 2021); Ind. Code Ann. § 20-33-13-4 (West 2022); Iowa Code Ann. § 261I.2 (West 2022); H.B. 2238, 2023 Leg. Sess. (Kan. 2023); Ky. Rev. Stat. Ann. § 164.2813 (West 2022); La. Stat. Ann. § 4:442 (2022); Miss. Code

7 In the United States, high school interscholastic athletics are generally

governed by state interscholastic athletic associations, such as the Idaho High

School Activities Association (IHSAA). The NCAA sets policies for member

colleges and universities in Idaho and elsewhere, including Boise State University

(BSU). Prior to the Act’s passage, IHSAA policy allowed transgender girls in 9–

12 athletics in Idaho to compete on girls’ teams after they had completed one year

of hormone therapy suppressing testosterone under the care of a physician. At that

time, NCAA policy similarly allowed transgender women attending member

colleges and universities in Idaho (and elsewhere) to compete on women’s teams

after one year of hormone therapy to suppress testosterone.5 Idaho itself had no

record of transgender women and girls participating in competitive women’s

sports.

Ann. § 37-97-1 (West 2021); Mo. Rev. Stat. 163.048 (2023); Mont. Code Ann. § 20-7-1306 (West 2021); H. 574 (N. C. 2023); Legis. Assemb. 1489, 68th Legis. Assemb., Reg. Sess. (N.D. 2023); Legis. Assemb. 1249, 68th Legis. Assemb., Reg. Sess. (N.D. 2023); Ohio Rev. Code § 3313.5320; Okla. Stat. Ann. tit. 70, § 27-106 (West 2022); S.C. Code Ann. § 59-1-500 (2022); S.D. Codified Laws § 13-67-1 (2022); Tenn. Code Ann. § 49-7-180 (2022); Tex. Educ. Code Ann. § 33.0834 (West 2022); Utah Code Ann. § 53g-6-902 (West 2022); W. Va. Code Ann. § 18- 2-25d (West 2021); S. 92, 67th Leg., Gen. Sess. (Wyo. 2023). 5 In April 2023, the NCAA updated its policy to require that transgender student- athletes meet the “sport-specific standard[s] (which may include testosterone levels, mitigation timelines and other aspects of sport-governing body policies)” of the national governing body of that sport. See Press Release, NCAA, Transgender Student-Athlete Participation Policy (April 17, 2023), https://www.ncaa.org/sports/2022/1/27/transgender-participation-policy.aspx (last visited May 3, 2024).

8 On February 13, 2020, Representative Barbara Ehardt introduced H.B. 500

in the Idaho House of Representatives. At the first hearing on the bill, Ty Jones,

Executive Director of the IHSAA, testified that no student in Idaho had ever

complained about participation in public school sports by transgender athletes, and

that no transgender athlete had ever competed in Idaho under the existing IHSAA

policy. Representative Ehardt acknowledged that she had no evidence that any

person in Idaho had ever disputed an athlete’s eligibility to play based on that

athlete’s gender.

After the Idaho House Committee approved the bill, Idaho Attorney General

Lawrence Wasden warned in a written opinion letter to the House that H.B. 500

raised serious constitutional questions due to the legislation’s disparate treatment

of transgender and intersex athletes and the potential invasion of all female

athletes’ privacy inherent in the sex dispute verification process. Nevertheless, the

bill proceeded to a debate and passed on the House floor on February 26, 2020.

After passage by the House, H.B. 500 was heard by the Senate State Affairs

Committee and sent to the full Idaho Senate on March 10, 2020. On March 11,

2020, the World Health Organization declared COVID-19 a pandemic and many

states adjourned legislative sessions indefinitely. The Idaho Senate remained in

session, however, and passed H.B. 500 as amended on March 16, 2020. The

9 House concurred in the Senate amendments on March 18, and the bill was

delivered to Idaho Governor Bradley Little on March 19, 2020.

As Governor Little considered the bill, critics questioned the legislation’s

findings and legality. Professor Dorianne Lambelet Coleman, whose work on

testosterone and athletics was cited in the legislative findings in support of the bill,

wrote to Governor Little urging him to veto the bill and explaining that her

research had been misinterpreted and misused in the legislative findings.

Similarly, five former Idaho Attorneys General implored Governor Little to veto

the Act, labeling it a “legally infirm statute.”6 Nonetheless, Governor Little signed

H.B. 500 into law on March 30, 2020, and it went into effect on July 1, 2020.

In enacting H.B. 500, the legislature made several findings based on

Professor Coleman’s study, including “that there are ‘inherent [biological]

differences between men and women,’” Idaho Code § 33-6202(1) (quoting United

States v. Virginia (VMI), 518 U.S. 515, 533 (1996)), and that men have “higher

natural levels of testosterone,” id. § 33-6202(4), which “have lifelong effects,

including those most important for success in sport,” id. § 33-6202(5). Relying on

Professor Coleman’s work, the legislature found that “[t]he benefit[] that natural

6 See also Tony Park et al., 5 Former Idaho Attorneys General Urge Transgender Bill Veto, Idaho Statesman (Mar. 17, 2020), https://www.idahostatesman.com/opinion/readers-opinion/article241267071.html (last visited May 23, 2023).

10 testosterone provides to male athletes is not diminished through the use of puberty

blockers and cross-sex hormones.” Id. § 33-6202(11). The legislature also found

that “women’s performances at the high[est] level [of athletics] will never match

those of men.” Id. § 33-6202(9) (quoting Valerie Thibault et al., Women and Men

in Sport Performance: The Gender Gap Has Not Evolved Since 1983, 9 J. of

Sports Sci. & Med. 214, 219 (2010)). The legislature concluded that “[h]aving

separate sex-specific teams furthers efforts to promote sex equality” by “providing

opportunities for female athletes to demonstrate their skill, strength, and athletic

abilities, while also providing them with opportunities to obtain recognition and

accolades, college scholarships, and numerous other long-term benefits that flow

from success in athletic endeavors.” Id. § 33-6202(12).

Three provisions of the Act are most salient to this appeal. First, the Act

provides that “[i]nterscholastic, intercollegiate, intramural, or club athletic teams or

sports” shall be organized “based on biological sex.” Id. § 33-6203(1). It

specifically provides that:

Interscholastic, intercollegiate, intramural, or club athletic teams or sports that are sponsored by a public primary or secondary school, a public institution of higher education, or any school or institution whose students or teams compete against a public school or institution of higher education shall be expressly designated as one (1) of the following based on biological sex:

(a) Males, men, or boys;

(b) Females, women, or girls; or

11 (c) Coed or mixed.

Id. The Act then provides that “[a]thletic teams or sports designated for females,

women, or girls shall not be open to students of the male sex.” Id. § 33-6203(2)

(the “categorical ban provision”). The Act’s provisions apply to all levels of

competition in Idaho state schools, including elementary school and club teams,

and do not include any limitation for transgender individuals who wish to

participate on athletic teams designated for men. Moreover, the provisions apply

not only to public schools, but also to nonpublic “school[s] or institution[s] whose

students or teams compete against a public school or institution of higher

education.” Id. § 33-6203(1).

Second, the Act creates a “sex verification” process to be invoked by any

individual who wishes to “dispute” a student’s sex, providing that:

A dispute regarding a student’s sex shall be resolved by the school or institution by requesting that the student provide a health examination and consent form or other statement signed by the student’s personal health care provider that shall verify the student’s biological sex. The health care provider may verify the student’s biological sex as part of a routine sports physical examination relying only on one (1) or more of the following: the student’s reproductive anatomy, genetic makeup, or normal endogenously produced testosterone levels.

Id. § 33-6203(3) (the “sex dispute verification provision”).

And third, the Act creates an enforcement mechanism to ensure compliance

with its provisions by establishing a private cause of action for any student who is

12 “deprived of an athletic opportunity or suffers any direct or indirect harm as a

result of a violation of [the Act].” Id. § 33-6205(1).

D.

On April 15, 2020, Lindsay Hecox (“Lindsay”), a transgender woman who

wishes to try out for the BSU women’s track and cross-country teams, and Jane

Doe (“Jane”), a cisgender woman who plays on high school varsity teams and

feared that her sex would be “disputed” under the Act due to her masculine

presentation, filed this lawsuit against Governor Little, Idaho Superintendent of

Public Instruction Sherri Ybarra, and various school officials at both the high

school and collegiate levels (collectively, “Idaho”). They sought a declaratory

judgment that the Act violates Title IX and the United States Constitution,

including the Equal Protection Clause, and preliminary and permanent injunctions

against the Act’s enforcement, as well as an award of costs, expenses, and

reasonable attorneys’ fees.

On May 26, 2020, Madison (“Madi”) Kenyon and Mary (“MK”) Marshall

(collectively, “the Intervenors”) were permitted to intervene in this case.

Intervenors are cisgender women residing in Idaho and collegiate athletes who run

track and cross-country on scholarship at Idaho State University. In 2019, both

athletes competed against and lost to June Eastwood, a transgender woman athlete

13 at the University of Montana, and found it a “discouraging” and “deflating”

experience.

On April 30, 2020, Plaintiffs moved for preliminary injunctive relief based

solely on their equal protection claims. The district court issued preliminary

injunctive relief in August 2020, ruling that both Plaintiffs were likely to succeed

on the merits of their equal protection claims and would suffer irreparable harm if

the injunction was not granted, and that the balance of equities weighed in favor of

an injunction. Idaho and the Intervenors (collectively, the “Appellants”) timely

appealed.

We first held oral argument in this appeal on May 3, 2021. At that time,

Lindsay informed the court that she had tried out for and failed to make the

women’s track team and that she subsequently withdrew from BSU classes in late

October 2020. Because the parties’ arguments raised several unanswered factual

questions as to whether Lindsay’s claim was moot, we remanded the case to the

district court for further factual development and findings on justiciability

questions on June 24, 2021.

On July 18, 2022, the district court issued factual findings and concluded

that Lindsay’s claim was not moot. We affirmed the district court’s determination

that Lindsay’s claim was not moot in an order issued on January 30, 2023. See

Hecox v. Little (Hecox II), No. 20-35813, 2023 WL 1097255, at *1 (9th Cir. Jan.

14 30, 2023).7 We then asked the parties to brief us on which claims remained for

decision in this appeal and any intervening authority. The parties agree that the

only issue that we must decide is whether the district court abused its discretion in

issuing the preliminary injunction.

II. STANDARD OF REVIEW

We review a district court’s grant of a preliminary injunction for an abuse

of discretion. Puente Arizona v. Arpaio, 821 F.3d 1098, 1103 (9th Cir. 2016).

That said, “legal issues underlying the injunction are reviewed de novo because a

district court would necessarily abuse its discretion if it based its ruling on an

erroneous view of law.” adidas Am., Inc. v. Skechers USA, Inc., 890 F.3d 747, 753

(9th Cir. 2018) (quoting GoTo.com, Inc. v. Walt Disney Co., 202 F.3d 1199, 1204

(9th Cir. 2000)); see also Sw. Voter Registration Educ. Project v. Shelley, 344 F.3d

914, 918 (9th Cir. 2003). We do “not ‘determine the ultimate merits’” of the case,

“but rather ‘determine only whether the district court correctly distilled the

7 In our January 2023 order, we determined that Lindsay’s claim was not moot when she withdrew from BSU in October 2020, because she expressed a concrete plan to re-enroll and try out for BSU sports teams. Hecox II, 2023 WL 1097255, at *1. Lindsay followed through on those plans by re-enrolling at BSU after she established Idaho state residency and training to participate in women’s sports teams. Id. Indeed, Lindsay planned to try out again for the BSU women’s cross- country and track teams in Fall 2023, and has been playing for the BSU women’s club soccer team since Fall 2022. Id., at *2. Absent the preliminary injunction against the Act’s enforcement, Lindsay would be banned from participating on the BSU women’s club soccer team. Id.

15 applicable rules of law and exercised permissible discretion in applying those rules

to the facts at hand.’” Saravia for A.H. v. Sessions, 905 F.3d 1137, 1141–42 (9th

Cir. 2018) (quoting Fyock v. Sunnyvale, 779 F.3d 991, 995 (9th Cir. 2015)).

However, we will reverse a grant of the preliminary injunction if the district court

“based its decision . . . on clearly erroneous findings of fact.” Does 1-5 v.

Chandler, 83 F.3d 1150, 1552 (9th Cir. 1996).

We review the scope of a preliminary injunction for an abuse of discretion.

California v. Azar, 911 F.3d 558, 567 (9th Cir. 2018).

III. PRELIMINARY INJUNCTION

“A preliminary injunction is ‘an extraordinary and drastic remedy, one that

should not be granted unless the movant, by a clear showing, carries the burden of

persuasion.’” Lopez v. Brewer, 680 F.3d 1068, 1072 (9th Cir. 2012) (quoting

Mazurek v. Armstrong, 520 U.S. 968, 972 (1997)). “A plaintiff seeking a

preliminary injunction must establish that he is likely to succeed on the merits, that

he is likely to suffer irreparable harm in the absence of preliminary relief, that the

balance of equities tips in his favor, and that an injunction is in the public interest.”

Winter v. Nat. Res. Def. Council, Inc., 555 U.S. 7, 20 (2008). The last two factors

“merge when the Government is the opposing party.” Nken v. Holder, 556 U.S.

418, 435 (2009).

A. Likelihood of Success on the Merits

16 The primary issue presented by this appeal is whether the district court

abused its discretion in concluding that Lindsay was likely to succeed on the merits

of her equal protection challenge. The Fourteenth Amendment provides that “[n]o

State shall . . . deny to any person within its jurisdiction the equal protection of the

laws.” U.S. Const. amend. XIV, § 1. In other words, “all persons similarly

situated should be treated alike.” City of Cleburne v. Cleburne Living Ctr., 473

U.S. 432, 439 (1985). The state may not discriminate against classes of people in

an “arbitrary or irrational” way or with the “bare . . . desire to harm a politically

unpopular group.” Id. at 446–47.

When considering an equal protection claim, we determine what level of

scrutiny applies to a classification under a law or policy, and then decide whether

the policy at issue survives that level of scrutiny. Our “general rule is that

legislation is presumed to be valid and will be sustained if the classification drawn

by the statute is rationally related to a legitimate state interest,” id. at 440,

otherwise known as rational basis review. However, as gender classifications

“generally provide[] no sensible ground for differential treatment,” id., “‘all

gender-based classifications today’ warrant ‘heightened scrutiny.’” VMI, 518 U.S.

at 555 (quoting J.E.B. v. Alabama ex rel. T.B., 511 U.S. 127, 136 (1994)). Under

heightened scrutiny, “a party seeking to uphold government action based on sex

17 must establish an ‘exceedingly persuasive justification’ for the classification.” Id.

at 524 (quoting Mississippi Univ. for Women v. Hogan, 458 U.S. 718, 724 (1982)).

1. Heightened scrutiny applies.

The district court did not err in concluding that heightened scrutiny applies

because the Act discriminates against transgender women by categorically

excluding them from female sports, as well as on the basis of sex by subjecting all

participants in female athletics, but no participants in male athletics, to invasive

sex verification procedures to implement that policy. Appellants contend that the

Act classifies based only on sex, not “transgender status,” and permissibly

excludes “biological males” from female sports under our precedent. See, e.g.,

Clark ex rel. Clark v. Arizona Interscholastic Ass’n (Clark I), 695 F.2d 1126,

1131–32 (9th Cir. 1982) (holding that excluding boys from a girls’ high school

volleyball team was permissible to redress past discrimination against women

athletes and to promote equal opportunity for women). We conclude that while the

Act certainly classifies on the basis of sex, it also classifies based on transgender

status, triggering heightened scrutiny on both grounds.

a. The Act discriminates based on transgender status.

Appellants argue that the Act does not discriminate based on transgender

status because “[t]he distinction and statutory classification is based entirely on

[biological] sex, not gender identity.” They assert that the Act’s definition of

18 “biological sex” describes only the “physiological differences between the sexes

relevant to athletics.” But the Act explicitly references transgender women, as did

its legislative proponents, and its text, structure, findings, and effect all

demonstrate that the purpose of the Act was to categorically ban transgender

women and girls from public school sports teams that correspond with their gender

identity.

A discriminatory purpose is shown when “the decisionmaker, in this case a

state legislature, selected or reaffirmed a particular course of action at least in part

‘because of,’ not merely ‘in spite of,’ its adverse effects upon an identifiable

group.” Pers. Adm’r of Massachusetts v. Feeney, 442 U.S. 256, 279 (1979). Here,

the district court found that “the law is directed at excluding women and girls who

are transgender, rather than on promoting sex equality and opportunities for

women.” Hecox I, 479 F. Supp. 3d at 983. This finding is not clearly erroneous.

Section 33-6202 straightforwardly sets forth the “legislative findings and

purpose” of the Act, and makes clear that its animating purpose was to ban

transgender women from “biologically female” teams. These findings explicitly

discuss transgender women athletes by stating that “a man [sic] who identifies as a

woman and is taking cross-sex hormones ‘ha[s] an absolute advantage’ over

female athletes,” and noting that “[t]he benefit[] that natural testosterone provides

19 to male athletes is not diminished through the use of puberty blockers and cross-

sex hormones.” Idaho Code § 33-6202(11).

During the legislative debate on H.B. 500, the Act’s supporters stated

repeatedly that the Act’s purpose was to ban transgender women athletes from

participating on female athletic teams in Idaho. Representative Ehardt, who

introduced the bill, characterized the law as a “preemptive” strike that would allow

Idaho to “remove [transgender women] and replace them with the young gal that

should have been on the team.” Representative Ehardt reiterated that the Act

would require transgender women to “compete on the side of those biological boys

and men with whom they look or, about whom they look alike.” Much of the

legislative debate centered around two transgender women athletes running track

in Connecticut high schools, as well as one running college track in Montana, and

the potential “threat” those athletes presented to female athletes in Idaho. When

Idaho’s then-Attorney General Wasden expressed concerns about the Act’s

constitutionality, he expressly described it as “targeted toward transgender and

intersex athletes.”

The plain language of section 33-6203 bans transgender women from

“biologically female” teams. The Act divides sports teams into three categories

based on biological sex: “(a) Males, men, or boys; (b) Females, women, or girls; or

(c) Coed or mixed.” Id. § 33-6203(1). Sports designated for “females, women, or

20 girls” are not open to students of the male sex. Id. § 33-6203(2). And the methods

for “verify[ing] the student’s biological sex” are restricted to “reproductive

anatomy, genetic makeup, or normal endogenously produced testosterone levels.”

Id. § 33-6203(3). However, most gender-affirming medical care for transgender

females, especially minors, will not or cannot alter the characteristics described in

the only three verification methods prescribed by the Act, thus effectively banning

transgender females from female sports.8 As the district court determined, “the

overwhelming majority of women who are transgender have XY chromosomes,”

which indicate the male sex, and transgender women cannot change that genetic

makeup when they transition. Hecox I, 479 F. Supp. 3d at 984. Similarly, as

medical expert Dr. Deanna Adkins opined, many transgender women and girls do

not undergo gender-affirming genital surgery to alter their external “reproductive

anatomy,” often because they cannot afford it or it is inappropriate for their

individual needs.

Further, because surgery cannot change transgender women’s internal

reproductive anatomy by creating ovaries, Dr. Adkins testified that transgender

women “typically continue to need estrogen therapy” even after surgery and can

8 In 2023, Idaho adopted legislation prohibiting minors from receiving gender- affirming medical care. See Idaho Code § 18-1506C, enjoined by Poe ex rel. Poe v. Labrador, 2023 WL 8935065, at *2 (D. Idaho Dec. 26, 2023), injunction modified in part sub nom. by Labrador v. Poe ex rel. Poe, 144 S. Ct. 921 (2024).

21 never alter their “endogenously produced”—or naturally produced—testosterone

levels. By contrast, the Act does not allow sex to be verified by a transgender

woman’s levels of circulating testosterone, which can be altered through medical

treatment. A transgender woman like Lindsay, for example, can lower her

circulating testosterone levels through hormone therapy to conform to elite athletic

regulatory guidelines, but cannot currently alter the endogenous testosterone that

her body naturally produces. Yet the district court found and the record before it

supports that circulating testosterone is the “one [sex-related] factor that a

consensus of the medical community appears to agree” actually affects athletic

performance. Id.

Appellants suggest that “biological sex” is a neutral and well-established

medical and legal concept, rather than one designed precisely by the Idaho

legislature to exclude transgender and intersex people.9 But the Act’s definition of

9 In supplemental briefing, Appellants also argue that the Supreme Court’s recent decisions in Dobbs v. Jackson Women’s Health Organization, 597 U.S. 215 (2022), and New York State Rifle & Pistol Ass’n v. Bruen, 597 U.S. 1 (2022), “are fatal to Hecox’s claim” because the ratifiers of the Fourteenth Amendment would have understood “male” to correspond to the definition of “biological male” written into the Act. We fail to see how Dobbs, a substantive due process decision about whether the federal Constitution protects a woman’s right to obtain an abortion, and Bruen, a Second Amendment decision about gun rights, are relevant to an equal protection claim based on sex discrimination, unless Appellants are suggesting that the Framers would have understood the term “biological sex” by reference to reproductive anatomy, genetic makeup, or normal endogenously produced testosterone levels. Indeed, the ratifiers of the Fourteenth Amendment would certainly not have understood the Act’s definition of “biological sex.” For

22 “biological sex” is likely an oversimplification of the complicated biological

reality of sex and gender. As Dr. Joshua Safer, Executive Director of the Center

for Transgender Medicine and Surgery at Mount Sinai, explained in his

declaration, citing the Endocrine Society Guidelines:

The phrase “biological sex” is an imprecise term that can cause confusion. A person’s sex encompasses the sum of several biological attributes, including sex chromosomes, certain genes, gonads, sex hormone levels, internal and external genitalia, other secondary sex

example, the drafters of the Fourteenth Amendment would have had no concept of what “endogenously produced testosterone levels” meant in 1868, because testosterone was not named and isolated as a hormone until 1935. See John M. Tomlinson, The Testosterone Story, Trends in Urology & Men’s Health 34, 35 (2012). Similarly, the ratifiers would not have understood how “genetic makeup” influences sex, as chromosomes were first discovered by Walther Flemming in 1882. D.W. Rudge, The Man Who Invented the Chromosome, 97 Heredity 136, 136 (2006) (reviewing Oren Harman, The Man Who Invented the Chromosome: A Life of Cyril Darlington (2004)). Moreover, there is evidence that transgender people have existed since ancient times. See generally Lauren Talalay, The Gendered Sea: Iconography, Gender, and Mediterranean Prehistory, in THE ARCHEOLOGY OF MEDITERRANEAN PREHISTORY 130–33 (Emma Blake & A. Bernard Knapp eds., 2005). Appellants appear to argue that because transgender people were marginalized in 1868, they should be afforded no constitutional protections on the basis of their transgender status. But this argument would undermine decades of Supreme Court precedent striking down laws that discriminate on the basis of sex. See Reed v. Reed, 404 U.S. 71, 76 (1971) (holding that an Idaho statute that preferenced men as administrators of estates “ma[d]e the very kind of arbitrary legislative choice forbidden by the Equal Protection Clause of the Fourteenth Amendment”); Frontiero v. Richardson, 411 U.S. 677, 687 (1973) (“[S]tatutory distinctions between the sexes often have the effect of invidiously relegating the entire class of females to inferior legal status without regard to the actual capabilities of its individual members.”); see also Weinberger v. Weisenfeld, 420 U.S. 636, 645 (1975); Craig v. Boren, 429 U.S. 190, 210 (1976); Duren v. Missouri, 439 U.S. 357, 360 (1979); VMI, 518 U.S. at 519.

23 characteristics, and gender identity. These attributes are not always aligned in the same direction.

Indeed, two percent of all babies are born “intersex,” or with “a wide range of

natural variations in physical traits—including external genitals, internal sex

organs, chromosomes, and hormones—that do not fit typical binary notions of

male and female bodies.” Br. of Amici Curiae InterACT at 3–4. Intersex people

who identify as women are equally banned under the Act from playing on Idaho

women’s teams. And while scientists are not fully certain why some people

identify as transgender, it appears likely that there is some biological

explanation—such as gestational exposure to elevated levels of testosterone—that

causes certain individuals to identify as a different gender than the one assigned to

them at birth. See AAP Br. at 14.

Finally, the Act’s discriminatory purpose is further evidenced by the Act’s

prohibition of “biological males” from female-designated teams because that

prohibition affects one group of athletes only—transgender women. See Crawford

v. Board of Education, 458 U.S. 527, 544 (1982) (explaining that the

“disproportionate effect of official action provides an important starting point” for

determining whether a “[discriminatory] purpose was [its] motivating factor”

(internal quotation marks omitted)). Before the Act’s passage, both the IHSAA

and the NCAA prohibited cisgender men and boys from participating on female-

designated sports teams. Both associations also had policies that allowed

24 transgender women and girls to participate on female athletic teams after

completing one year of hormone therapy to suppress testosterone levels. Giving

effect to the Act still prohibits men and boys from participating on female athletic

teams. But all transgender girls and women, even those who were previously

eligible consistent with the IHSAA and NCAA policies, are now barred from

female athletics. The Act’s only contribution to Idaho’s student-athletic landscape

is to entirely exclude transgender women and girls from participating on female

sports teams. And where a statute’s “undisputed purpose [] and only effect . . . is

to exclude transgender girls . . . from participation on girls sports teams,” that

statute discriminates on the basis of transgender status. B.P.J. ex rel. Jackson v. W.

Va. State Bd. of Educ., 98 F.4th 542, 556 (4th Cir. 2024).

In addition to having a discriminatory purpose and effect, the Act is also

facially discriminatory against transgender female athletes. We have previously

rejected an argument like that Appellants raise here—that because section 33-6203

uses “biological sex” in place of the word “transgender,” it is not targeted at

excluding transgender girls and women. In Latta v. Otter, 771 F.3d 456 (9th Cir.

2014), we held that Idaho and Nevada laws that banned same-sex marriage facially

discriminated on the basis of sexual orientation, even though the laws did so by

classifying couples based on “procreative capacity” instead of sexual orientation.

Id. at 467–68. We explained:

25 Effectively if not explicitly, [defendants] assert that while these laws may disadvantage same-sex couples and their children, heightened scrutiny is not appropriate because differential treatment by sexual orientation is an incidental effect of, but not the reason for, those laws. However, the laws at issue distinguish on their face between opposite- sex couples, who are permitted to marry and whose out-of-state marriages are recognized, and same-sex couples, who are not permitted to marry and whose marriages are not recognized. Whether facial discrimination exists “does not depend on why” a policy discriminates, “but rather on the explicit terms of the discrimination.” Hence, while the procreative capacity distinction that defendants seek to draw could represent a justification for the discrimination worked by the laws, it cannot overcome the inescapable conclusion that Idaho and Nevada do discriminate on the basis of sexual orientation.

Id. at 467–68 (quoting Int’l Union, United Auto., Aerospace & Agr. Implement

Workers of Am., UAW v. Johnson Controls, Inc., 499 U.S. 187, 199 (1991)). Here,

the Act’s use of “biological sex” functions as a form of “[p]roxy discrimination.”

Pac. Shores Props., LLC v. City of Newport Beach, 730 F.3d 1142, 1160 n.23 (9th

Cir. 2013). The definition of “biological sex” in the Act is written with “seemingly

neutral criteria that are so closely associated with the disfavored group that

discrimination on the basis of such criteria is, constructively, facial discrimination

against the disfavored group.” Id.; see also Lawrence v. Texas, 539 U.S. 558, 575

(2003) (“When homosexual conduct is made criminal by the law of the State, that

declaration in and of itself is an invitation to subject homosexual persons to

discrimination . . . .”). The Act’s specific classification of “biological sex” has

similarly been carefully drawn to target transgender women and girls, even if it

does not use the word “transgender” in the definition.

26 Adams ex rel. Kasper v. School Board of St. Johns County, 57 F.4th 791

(11th Cir. 2022) (en banc), upon which Appellants rely to support their argument

that the Act does not discriminate against transgender girls or women, is

inapposite. There, the Eleventh Circuit upheld a lower court order rejecting an

equal protection challenge to a K-12 school policy that provided female, male, and

sex-neutral bathrooms and required male students to use the male-designated

bathrooms, required female students to use the female bathrooms, and

accommodated transgender students with the sex-neutral bathrooms. See id. at

797. The policy defined “male” and “female” as the gender identified on a

student’s birth certificate. See id. The Eleventh Circuit rejected the argument that

the policy unconstitutionally discriminated on the basis of transgender status

because it was “substantially related” to the school district’s important interest in

securing its pupils’ privacy and welfare and was not targeted at transgender

students—at most, it had a disparate impact upon them which did not rise to the

level of a constitutional violation because no animus was shown. See id. at 811.

Importantly, in Adams—as opposed to here—there was “no [record] evidence

suggesting that the School Board enacted the [] policy because of . . . its adverse

effects upon transgender students.” Id. at 810 (second alteration in original)

(internal quotation marks omitted). To the contrary, the school district in Adams

27 had studied the issues raised by the LGBTQ community and had also enacted

policies that affirmatively accommodated transgender students.10

Appellants likewise misrely on a footnote in Geduldig v. Aiello, 417 U.S.

484 (1974), for the proposition that a legislative classification based on biological

sex is not a classification based on transgender status. See id. at 496 n.20. In

Geduldig, the Supreme Court stated that a classification based on pregnancy is not

per se a classification based on sex, even though “it is true that only women can

become pregnant.” Id. However, the Court held that “distinctions involving

pregnancy” that are “mere pretexts designed to effect an invidious discrimination”

are subject to heightened scrutiny. Id. Here, it appears that the definition of

“biological sex” was designed precisely as a pretext to exclude transgender women

from women’s athletics—a classification that Geduldig prohibits.

Finally, Appellants contend that the Act does not discriminate based on

transgender status because the “Act does not prohibit biologically female athletes

who identify as male from competing on male sports teams consistent with their

gender identity.” But a law is not immune to an equal protection challenge if it

discriminates only against some members of a protected class but not others. See,

e.g., Rice v. Cayetano, 528 U.S. 495, 516–17 (2000) (“Simply because a class . . .

10 Although Adams is plainly distinguishable, we express no view on the merits of the decision.

28 does not include all members of [a] race does not suffice to make the classification

race neutral.”); Nyquist v. Mauclet, 432 U.S. 1, 7–9 (1977) (holding that singling

out some but not all undocumented immigrants for discrimination constituted a

“classification based on alienage”); Mathews v. Lucas, 427 U.S. 495, 504 n.11

(1976) (“That the statutory classifications challenged here discriminate among

illegitimate children does not mean, of course, that they are not also properly

described as discriminating between legitimate and illegitimate children.”).

b. Heightened scrutiny applies because the Act discriminates on the basis of transgender status.

We have previously held that heightened scrutiny applies to laws that

discriminate on the basis of transgender status, reasoning that gender identity is at

least a “quasi-suspect class.” Karnoski v. Trump, 926 F.3d 1180, 1200–01 (9th

Cir. 2019).

In Karnoski, we reviewed an injunction against the implementation of a

2017 Presidential Memorandum and Departments of Defense and Homeland

Security policies that effectively precluded transgender individuals from serving in

the U.S. military. Id. at 1189. The district court had applied strict scrutiny in

enjoining the policy, while the government argued that the policy should be

reviewed under a rational basis standard. Id. at 1200. We held that because the

implementing policy “on its face treats transgender persons differently than other

persons . . . something more than rational basis but less than strict scrutiny

29 applies.” Id. at 1201. We therefore adopted the heightened scrutiny approach of

VMI and Witt v. Department of Air Force, 527 F.3d 806, 818 (9th Cir. 2008), to

review the military’s ban on transgender persons who experienced gender

dysphoria or who have undergone gender transition.11 Id. We are thus compelled

to review the constitutionality of the Act under heightened scrutiny as it classifies

based on transgender status.

Moreover, discrimination on the basis of transgender status is a form of sex-

based discrimination. It is well-established that sex-based classifications are

subject to heightened scrutiny. See VMI, 518 U.S. at 533–34. The Supreme Court

recently held in the Title VII context that “it is impossible to discriminate against a

person for being . . . transgender without discriminating against that individual

based on sex.” Bostock v. Clayton County, 590 U.S. 644, 660 (2020).12 Indeed,

11 The Supreme Court determined in VMI that for “cases of official classification based on gender” a reviewing court must apply a “heightened review standard” and determine whether the state has demonstrated an “exceedingly persuasive justification” for the classification. 518 U.S. at 533–34. In Witt, we applied a “heightened scrutiny” approach to the military’s “Don’t Ask, Don’t Tell” policy for gay and lesbian servicemembers, determining that “when the government attempts to intrude upon the personal and private lives of homosexuals . . . the government must advance an important governmental interest, the intrusion must significantly further that interest, and the intrusion must be necessary to further that interest.” 527 F.3d at 819. 12 See also Nondiscrimination on the Basis of Sex in Education Programs or Activities Receiving Federal Financial Assistance, 87 Fed. Reg. 41,390, 41,571 (Aug. 1, 2024) (to be codified at 34 C.F.R. pt. 106) (clarifying that “discrimination on the basis of sex” under Title IX includes discrimination based on “sex stereotypes, sex characteristics . . . and gender identity”).

30 “[m]any courts . . . have held that various forms of discrimination against

transgender individuals constitute sex-based discrimination for purposes of the

Equal Protection Clause because such policies punish transgender persons for

gender non-conformity, thereby relying on sex stereotypes.” Grimm v. Gloucester

Cnty. Sch. Bd., 972 F.3d 586, 608 (4th Cir. 2020) (applying heightened scrutiny to

a bathroom policy); see also Whitaker ex rel. Whitaker v. Kenosha Unified Sch.

Dist. No. 1 Bd. of Educ., 858 F.3d 1034, 1051 (7th Cir. 2017), abrogated on other

grounds, Illinois Republican Party v. Pritzker, 972 F.3d 760 (7th Cir. 2020)

(same); Brandt ex rel. Brandt v. Rutledge, 47 F.4th 661, 670–71 & n.4 (8th Cir.

2022) (applying heightened scrutiny to affirm a preliminary injunction against a

law that prohibited “gender transition procedures” because the law discriminated

on the basis of sex); Eknes-Tucker v. Marshall, 603 F. Supp. 3d 1131, 1147 (M.D.

Ala. 2022) (applying heightened scrutiny to a law that prohibited various medical

treatments for gender dysphoria in minors).13

c. Heightened scrutiny applies because the Act discriminates against all participants in female sports.

13 Both Idaho and the Intervenors note that the Eleventh Circuit expressed “grave doubt” in a footnote in Adams that transgender people constitute a “quasi-suspect class.” Adams, 57 F.4th at 803 n.5 (internal quotation marks omitted). This dictum is unpersuasive, as the Eleventh Circuit declined to decide the issue or further opine on its “doubt.” In any event, as a three-judge panel we cannot overrule the binding precedent of our circuit. See Miller v. Gammie, 335 F.3d 889, 899 (9th Cir. 2003).

31 In addition to discriminating on the basis of transgender status, the Act

discriminates on the basis of sex, because only students who participate on female

designated sports teams, and not students who participate on male designated

sports teams, are subject to the sex dispute verification process. The Act expressly

states that only “[a]thletic teams or sports designated for females, women, or girls

shall not be open to students of the male sex.” Idaho Code § 33-6203(2). The Act

does not ban “biological females” from “teams or sports designated for males.”

Therefore, transgender and cisgender men who compete on male-designated teams

are not subject to the sex dispute verification process. The sex dispute verification

process simply does not apply to male designated sports teams.

The Act thus classifies on the basis of sex by subjecting only participants in

women’s and girls’ sports, whether cisgender or transgender, to the risk and

humiliation of having their sex “disputed” and then suffering intrusive medical

testing as a prerequisite for participation on school sports teams. And where

women’s and girls’ sports are subject to separate requirements for educational

opportunities that are “unequal in tangible and intangible” ways from those for

men, those requirements are tested under heightened scrutiny. VMI, 518 U.S. at

547.

2. The Act likely does not survive heightened scrutiny.

32 The district court correctly concluded that the Act likely does not survive

heightened scrutiny. Heightened scrutiny is a “demanding” standard, with the

burden “rest[ing] entirely on the State” to demonstrate an “exceedingly persuasive”

justification for its differential treatment. VMI, 518 U.S. at 533. To survive

heightened scrutiny, the government must demonstrate “that the [challenged]

classification serves important governmental objectives and that the discriminatory

means employed are substantially related to the achievement of those objectives.”

Id. at 516 (alteration in original) (internal quotation marks and citations omitted).

Our review under heightened scrutiny is an extremely fact-bound test, requiring us

to “examine [a policy’s] actual purposes and carefully consider the resulting

inequality to ensure our most fundamental institutions neither send nor reinforce

messages of stigma or second-class status.” SmithKline Beecham Corp. v. Abbott

Labs., 740 F.3d 471, 483 (9th Cir. 2014).

Appellants contend that, “[d]ue to the average physiological differences”

between men and women, the Act substantially advances the important state

interest of “promot[ing] sex equality . . . by providing opportunities for female

athletes to demonstrate their skill, strength, and athletic abilities [and]

opportunities to obtain recognition and accolades, college scholarships, and the

numerous other long-term benefits that flow from success in athletic endeavors.”

Idaho Code § 33-6202(12). We have previously held that furthering women’s

33 equality and promoting fairness in female athletic teams is an important state

interest. Clark I, 695 F.2d at 1131. However, on the record before us, the district

court correctly determined that the Act’s means—categorically banning

transgender women and girls from all female athletic teams and subjecting all

participants in female athletics to intrusive sex verification procedures—likely are

not substantially related to, and in fact undermine, those asserted objectives.

a. Clark I and Clark II do not control the outcome of Lindsay’s claim.

Our decisions in Clark I and Clark ex rel. Clark v. Arizona Interscholastic

Ass’n (Clark II), 886 F.2d 1191 (9th Cir. 1989), are inapposite. In Clark I and

Clark II, we held that public high schools could constitutionally prohibit cisgender

male student athletes from participation on women’s teams in order to further the

important government interest of “redressing past discrimination against women in

athletics and promoting equality of opportunity between the sexes.” Clark I, 695

F.2d at 1131.

Specifically in Clark I, we held that an Arizona Interscholastic Association

policy that separated high school volleyball teams by gender and prohibited boys

from playing on girls’ teams did not violate the Equal Protection Clause. Clark I,

695 F.2d at 1127. There, Clark wished to play on the girls’ volleyball team

because his particular high school did not offer boys’ volleyball teams. Id. We

first recognized that, in applying heightened scrutiny, “the Supreme Court is

34 willing to take into account actual differences between the sexes, including

physical ones.” Id. at 1229 (citing Michael M. v. Sonoma Cnty. Superior Ct., 450

U.S. 464, 468–69 (1981) (upholding a statutory rape statute that held only males

culpable because only women can become pregnant, thus furthering the

government’s interest in preventing teen pregnancy)). We concluded that general

gender separation in school sports was substantially related to the government’s

interest in women’s equality in athletics. Id. at 1131. We reasoned that “due to

average physiological differences, males would displace females to a substantial

extent if they were allowed to compete for positions on the volleyball team.” Id.

Thus, if men were allowed to compete on the women’s teams, women’s overall

athletic opportunities would decrease, while men’s overall athletic opportunities

would remain greater than women’s.

Eight years later, in Clark II, the original Clark I plaintiff’s brother brought a

second “mystifying” action challenging the same policy, arguing that the state

“ha[d] been wholly deficient in its efforts to overcome the effects of past

discrimination against women in interscholastic athletics, and that this failure

vitiate[d] its justification for a girls-only volleyball team.” Clark II, 886 F.2d at

1193. Applying Clark I, we affirmed that the gender classification for Arizona

school sports was constitutional. Id. at 1194.

35 Appellants argue that “[t]he only difference between Hecox and the Clark

brothers is gender identity,” which does not change the physiological advantages

that “biological males” have over cisgender women. But this is a false assumption.

First, Lindsay takes medically prescribed hormone therapy to suppress her

testosterone and raise her estrogen levels. This treatment has lowered her

circulating testosterone levels—which impact athletic prowess and have slowed

her racing times by at least “five to ten percent”—and her testosterone levels were

“well below the levels required to meet NCAA eligibility for cross country and

track” in Fall 2022, as the district court found. See Hecox I, 479 F. Supp. 3d at

946. Lindsay’s treatment has dramatically altered her bodily systems and

secondary sex characteristics. As the district court found, “it is not clear that

transgender women who suppress their testosterone have significant physiological

advantages over cisgender women,” unlike the cisgender boys at issue in Clark I

and Clark II. Id. at 978. The record in Clark I made clear that sex was a valid

proxy for average physiological differences between men and women. Here, by

contrast, the district court found that the ban on transgender female athletes applies

broadly to many students who do not have athletic advantages over cisgender

female athletes. Thus, a faithful application of Clark I supports, rather than

undermines, the district court’s reasoning here.

36 Second, as the district court noted, transgender women, “like women

generally . . . have historically been discriminated against, not favored.” Id. at 977.

A recent study by the CDC concluded that “transgender students reported

significantly higher incidents of being bullied, feeling unsafe traveling to or from

school, being threatened with a weapon at school, and being made to engage in

unwanted sexual relations.” Br. of Amici Curiae GLBTQ Legal Advocates &

Defenders and the National Center for Lesbian Rights, at 9; see also Whitaker, 858

F.3d at 1051 (“There is no denying that transgender individuals face

discrimination, harassment, and violence because of their gender identity.”).

Unlike the policy in Clark I, the Act perpetuates historic discrimination against

both cisgender and transgender women by categorically excluding transgender

women from athletic competition and subjecting all participants in women’s

athletics to an invasive sex dispute verification process.

Moreover, the district court correctly found that “under the Act, women and

girls who are transgender will not be able to participate in any school sports, unlike

the boys in Clark I, who generally had equal [or greater] athletic opportunities.”

Hecox I, 479 F. Supp. 3d at 977. Here, unlike in Clark I, transgender women are

not being denied one “particular opportunity” to participate on women’s teams

even though their “overall opportunity is not inferior” to that of women. Clark I,

695 F.2d at 1126. As a practical matter, the Act bars transgender women and girls

37 in Idaho from all participation in student athletics—under its explicit terms, they

cannot play on teams that conform to their transgender status. The argument

advanced by Representative Ehardt that the Act does not discriminate against

transgender women because they can still play on men’s teams is akin to the

argument we rejected in Latta, that same-sex marriage bans do not discriminate

against gay men because they are free to marry someone of the opposite sex. See

Latta, 771 F.3d at 467 (holding unconstitutional two marriage bans that

“distinguish on their face between opposite-sex couples who are permitted to

marry and whose out-of-state marriages are recognized, and same-sex couples,

who are not permitted to marry and whose marriages are not recognized”). As

medical expert Dr. Jack Turban stated, “forcing [transgender students] to play on a

sports team that does not match their gender identity would damage their mental

health” by “forcing them to express themselves as cisgender.” Lindsay declared

that she would never compete on a men’s team, as it would be “embarrassing and

painful to be forced onto a team for men—like constantly wearing a big sign that

says ‘this person is not a “real” woman.’”

The district court also found that, on the record before it, “transgender

women have not and could not ‘displace’ cisgender women in athletics ‘to a

substantial extent.’” Hecox I, 479 F. Supp. 3d at 977 (quoting Clark I, 695 F.2d at

1131). Appellants misrely on a single line from Clark II to argue that the

38 participation of just one transgender woman on a team risks displacing any

individual cisgender woman: “If males are permitted to displace females on the

school volleyball team even to the extent of one player like Clark, the goal of equal

participation by females in interscholastic athletics is set back, not advanced.”

Clark II, 886 F.2d at 1193. This statement, however, was made in response to the

argument in Clark II that because sex separation had not fully met Arizona’s goal

of equality of participation in sports, Arizona no longer had an important interest in

the policy. We did not think Clark’s proposed remedy for the inequality of

opportunities for female athletes—allowing him to play on the girls’ teams—

would advance the “goal of equal participation by females in interscholastic

sports.” Id. Because transgender women represent about 0.6 percent of the

general population, the district court did not err in finding it unlikely that they

would displace cisgender women from women’s sports.

The only issue we decided in Clark—whether a sex-based classification was

constitutionally permissible—is not in dispute here. Lindsay does not challenge

the exclusion of cisgender males from female-designated sports. The question that

is presented here—whether a classification based on transgender status is

constitutionally permissible—is one that was not presented or discussed in Clark.

b. The Act is likely not substantially related to an important government interest.

39 Nor did the district court err in concluding that the Act likely fails

heightened scrutiny because it is not substantially related to its stated goals of

equal participation and opportunities for women athletes. The district court

concluded that the Act’s categorical ban does not advance its asserted objectives

based on three factual findings, none of which is “illogical, implausible, or without

support in inferences that may be drawn from the facts in the record.” Pom

Wonderful LLC v. Hubbard, 775 F.3d 1118, 1123 (9th Cir. 2014) (citation

omitted). Moreover, the Act’s sweeping prohibition on transgender female athletes

in Idaho—encompassing all students, regardless of whether they have gone

through puberty or hormone therapy, without any evidence of transgender athletes

displacing female athletes in Idaho, and enforced through a mechanism that

subjects all participants in female athletics to the threat of an invasive physical

examination—is likely too unrelated to the State’s legitimate objectives to satisfy

heightened scrutiny.

First, the district court found that there was scientifically “no evidence to

suggest a categorical bar against a transgender female athlete’s participation in

sports is required in order to promote ‘sex equality’ or to ‘protect athletic

opportunities for females’ in Idaho.” Hecox I, 479 F. Supp. 3d at 978–79.

Appellants argue that the district court misread the available medical evidence,

which they contend demonstrates that endogenous testosterone levels give

40 “biological males” a permanent athletic advantage over cisgender women.

However, the district court did not clearly err by relying upon the testimony of a

medical expert, Dr. Safer, who testified that there was a medical consensus that the

“primary known driver of differences in athletic performance between elite male

athletes and elite female athletes” is “the difference in [circulating] testosterone”

levels, as opposed to “endogenously produced” testosterone levels, and “[a]

person’s genetic make-up and internal and external reproductive anatomy are not

useful indicators of athletic performance and have not been used in elite

competition for decades.” The district court reasonably credited Dr. Safer’s

opinion that a transgender woman who received hormone therapy to lower her

circulating levels of testosterone would likely not have “physiological

characteristics” that would lead to enhanced athletic prowess when compared to a

cisgender woman.

Appellants presented contrary medical testimony by Dr. Gregory Brown that

hormone therapy suppression did not eliminate all of the physiological advantages

that an individual experiences through male puberty. However, as the district court

found, Dr. Brown’s opinion was not supported by the studies he relied upon,

because the majority of the studies he cited discussed the average differences

between male and female athletes in general, not the difference between

transgender and cisgender women athletes. And one study that he cited—the

41 Handelsman study—actually came to the opposite conclusion, concluding that

“evidence makes it highly likely that the sex difference in circulating testosterone

of adults explains most, if not all, of the sex differences in sporting performance.”

The studies that the Idaho legislature relied upon to conclude that the

benefits of “natural testosterone” could not be diminished through hormone

therapy were likewise flawed. For example, one of the studies was altered after

peer review to remove its conclusions regarding transgender athletes, and, as Idaho

concedes, that “study and its findings were not based specifically on transgender

athletes.” The legislature also relied on a study by Professor Coleman, who

personally urged Governor Little to veto the bill because the legislature had

misinterpreted her work.

Moreover, as the district court found, the Act sweeps much more broadly

than simply excluding transgender women who have gone through “endogenous

puberty.” The Act’s categorical ban includes transgender students who are young

girls in elementary school or even kindergarten. Other transgender women take

puberty blockers and never experience endogenous puberty, yet the Act

indiscriminately bars them from participation in women’s student athletics,

regardless of their testosterone levels. Although the scientific understanding of

transgender women’s potential physiological advantage is fast-evolving and

somewhat inconclusive, we are limited to reviewing the record before the district

42 court. And the record in this case does not ineluctably lead to the conclusion that

all transgender women, including those like Lindsay who receive hormone therapy,

have a physiological advantage over cisgender women.

Second, as the district court found, there was very little anecdotal evidence

at the time of the Act’s passage that transgender women had displaced or were

displacing cisgender women in sports or scholarships or like opportunities. In

2020, both the IOC and the NCAA required transgender women to suppress their

testosterone for only a year for eligibility to compete on women’s teams.14 The

record before the district court includes anecdotal evidence of only four

transgender athletes who had ever competed in cisgender women’s sports,

14 Although today the IOC and NCAA policies evaluate eligibility for transgender participation in athletics on a sport-by-sport basis, neither policy endorses the categorical exclusion of transgender women. They instead favor an “evidence- based approach” with “no presumption of advantage.” Int’l Olympics Comm., IOC Framework on Fairness, Inclusion and Non-Discrimination on the Basis of Gender Identity and Sex Variations 4 (2021), https://stillmed.olympics.com/media/Documents/Beyond-the-Games/Human- Rights/IOC-Framework-Fairness-Inclusion-Non-discrimination-2021.pdf#page=4 (last visited June 6, 2023); see also Nat’l Collegiate Athletics Ass’n, Transgender Student-Athlete Participation Policy (April 17, 2023), https://www.ncaa.org/sports/2022/1/27/transgender-participation-policy.aspx (last visited May 24, 2023). And while the World Athletics Council, the international governing body for track and field, recently adopted a more stringent policy of categorically excluding post-pubescent transgender women from elite athletic competitions, its policy does not bar transgender women who have not experienced endogenous puberty from eligibility. See Press Release, World Athletics Counsel, World Athletics Council Decides on Russia, Belarus, and Female Eligibility (Mar. 23, 2023), https://worldathletics.org/news/press-releases/council-meeting-march- 2023-russia-belarus-female-eligibility (last visited May 24, 2023).

43 including two high school runners who competed in Connecticut and were

subsequently defeated by cisgender women in competition. While the Intervenors

state they were defeated by a transgender athlete, June Eastwood, in a running

competition at the University of Montana, Eastwood eventually lost to a different

cisgender athlete in that same competition. Lindsay’s own athletic career belies

the contention that transgender women who have undergone male puberty have an

absolute advantage over cisgender women: she has never qualified for BSU’s track

team despite trying out.

There is likewise no evidence in the record of a transgender woman

receiving an athletic scholarship over a cisgender woman in Idaho. Moreover, as

the district court noted, the Act’s broad sweep—banning transgender women’s

participation not just in high school and college athletics, but elementary school

and club sports—“belies any genuine concern with an impact on athletic

scholarships,” which are relevant to only a small portion of the competitive teams

encompassed by the Act. Hecox I, 479 F. Supp. 3d at 983.

Of course, when applying heightened scrutiny, we “must accord substantial

deference to the predictive judgments” of legislative bodies. Turner Broad. Sys.,

Inc. v. FCC, 512 U.S. 622, 665 (1994). But this does not “insulate[]” predictive

judgments “from meaningful judicial review altogether.” Id. at 666.

“[U]nsupported legislative conclusions as to whether particular policies will have

44 societal effects of the sort at issue in this case—determinations which often, as

here, implicate constitutional rights—have not been afforded deference by the

[Supreme] Court.” Latta, 771 F.3d at 469; see also Lopez-Valenzuela v. Arpaio,

770 F.3d 772, 784 (9th Cir. 2014) (en banc) (“[T]he absence of any credible

showing that the [challenged law] addressed a particularly acute problem” was

“quite relevant” to a showing that the law did not survive heightened scrutiny.). A

vague, unsubstantiated concern that transgender women might one day dominate

women’s athletics is insufficient to satisfy heightened scrutiny.

Third, the district court questioned the Act’s true objectives, finding that

Idaho’s interest was not in “promoting sex equality” but in “excluding transgender

women and girls from women’s sports entirely.” Hecox I, 479 F. Supp. 3d at 983.

Before the Act’s passage, the existing NCAA and Idaho state rules governed

transgender women’s participation as measured by circulating testosterone levels,

and there was no record evidence that transgender women and girls threatened to

dominate female student athletics. The record indicates that Idaho may have

wished “to convey a message of disfavor” toward transgender women and girls,

who are a minority in this country. See Latta, 771 F.3d at 476. And “[t]his is a

45 message that Idaho . . . simply may not send” through unjustifiable

discrimination.15 Id. at 476.

Further evidencing the lack of means-ends fit between the categorical ban of

transgender female athletes and the Legislature’s purported purpose of promoting

athletic equality is the Act’s overly broad enforcement mechanism: the sex dispute

verification provision, which is integral to the Act’s operation.16 Under the Act,

15 The Fourth Circuit recently held that West Virginia’s categorical ban could not be applied to “prevent a 13-year-old transgender girl who takes puberty blocking medication and has publicly identified as a girl since the third grade from participating in her school’s cross country and track teams.” B.P.J. by Jackson v. W. Va. State Bd. of Educ., 98 F.4th 542, 550 (4th Cir. 2024). Other federal and state courts have similarly enjoined transgender sports bans, and no categorical ban has yet been upheld on appeal. See Doe v. Horne, No. 23-16026 (9th Cir.) (pending appeal challenging the preliminary injunction against Arizona’s statute regulating transgender female athlete participation); A.M. by E.M. v. Indianapolis Pub. Sch., 617 F. Supp. 3d 950, 969 (S.D. Ind. July 26, 2022), appeal dismissed, No. 22-2332, 2023 WL 371646, at *1 (7th Cir. Jan. 19, 2023) (granting a preliminary injunction against transgender participation in athletics under Title IX); Roe v. Utah High Sch. Activities Ass’n, No. 220903262, 2022 WL 3907182, at *1 (Utah Dist. Ct. Aug. 19, 2022) (granting a preliminary injunction against a categorical ban under the Utah Constitution’s equivalent of an equal protection clause); see also Barrett v. Montana, No. DV-21-581B, at *5–7 (Mont. Dist. Ct. Sept. 14, 2022) (granting summary judgment against a categorical ban on the ground that only Montana public university officials have the authority to regulate athletic competition in public universities). 16 In its petition for rehearing en banc, Idaho argues that Lindsay lacks Article III standing to challenge the dispute and sex verification procedures. Pet. Reh’g En Banc at 2, 15–16. We need not address this argument because we do not consider whether the dispute and sex verification procedures constitute an independent equal protection violation; we address only whether Lindsay is likely to succeed on her equal protection challenge to the transgender ban as a whole. Furthermore, to the extent Idaho challenges Lindsay’s standing to challenge section 33-6203(3), we reject the argument. Lindsay has standing to challenge section 33-6203(3) because

46 anyone—be it a teammate, coach, parent, or a member of an opposing team—may

“dispute” a player’s “biological sex,” requiring that player to visit her “personal

health care provider . . . [who will] verify the student’s biological sex” through the

player’s “reproductive anatomy, genetic makeup, or normal endogenously

produced testosterone levels.” Idaho Code § 33-6203(3). The Act’s express terms

limit the verification procedure to a “routine sports physical examination” by

“relying only on one (1) or more of the following: the student’s reproductive

anatomy, genetic makeup, or normal endogenously produced testosterone levels.”

Id. (emphasis added). By its plain text, the Act provides that a student’s sex can be

verified exclusively by these three enumerated methods. Thus, the district court

reasonably found incredulous defense counsel’s argument that the Act merely

required Lindsay to obtain a letter from her doctor stating that Lindsay “is female.”

Hecox I, 479 F. Supp. 3d at 964 & n.19, 983. If that was all that was required to

verify a student’s sex under the Act, Lindsay could simply obtain such a statement

and the Act (and this appeal) would be rendered meaningless.

Any one of the three exclusive procedures requires far more than a “routine

sports physical” exam or simply asking whether a patient is female or not. As

it is an integral part of the transgender ban that she indisputably has standing to challenge—it supplies “the Act’s definition of ‘biological sex.’” Hecox I, 479 F. Supp. 3d at 984.

47 Lindsay’s medical expert Dr. Sara Swobada described, analyzing a student’s

“genetic makeup” would require referral to a “pediatric endocrinologist” who

would conduct a “chromosomal microarray” that would reveal a “range of genetic

conditions” beyond sex chromosomes. Hormone testing would also require an

“pediatric endocrinologist,” and is not a “routine part of any medical evaluation.”

Of course, the expense and burden of these tests would be borne only by the

students who play female athletics and their families.

Requiring a student to find a medical practitioner to examine their

reproductive anatomy, which is what a typical gynecological exam entails, is

unconscionably invasive, with the potential to traumatize young girls and women.

As Dr. Swobada opined, examining a female patient’s “reproductive anatomy”

would necessitate inspecting a student athlete’s genitalia and conducting a pelvic

examination or transvaginal ultrasound to determine whether that student has

ovaries. She further explained that pelvic examinations for young patients are

generally not required for minors, including adolescents, and are only conducted

when medically necessary “with sedation and appropriate comfort measures to

limit psychological trauma.” Yet the Act’s sex verification process subjects girls

as young as elementary schoolers to unnecessary gynecological examinations

merely because an individual “disputes” their sex.

48 The psychological burden of these searches falls not only on transgender

women like Lindsay but also on all women and girls who play female athletics. As

amici describe, “[s]ex verification procedures have a long, checkered history in

female sports that continue to this day.” Br. of Amici Curiae National Women’s

Law Center, et al. at 15. In the 1960s, the IOC would force female athletes to strip

and parade in front of a panel of doctors to prove that they were, in fact, women.

Id. The process was discontinued after a public outcry. Id. One intersex athlete

who failed a sex verification procedure described being “so ‘tormented’ and

‘unbearably embarrassed’ that ‘she attempted suicide’ by ‘swallowing poison.’”

Id. at 17 (quoting Ruth Padawer, The Humiliating Practice of Sex-Testing Female

Athletes, N.Y. Times Magazine (June 28, 2016)). Tellingly, while many athletic

organizations have tightened their rules for transgender women’s competition since

2020, none appears to have instituted a process that required gynecological

examinations or invasive physical examinations.17 Of the twenty-four other states

that have passed restrictions on transgender women’s participation in women’s

sports, none has authorized a similar sex verification process.18 Idaho has not

17 The IOC has expressly disavowed invasive sex verification procedures, stating that “[c]riteria to determine eligibility for a gender category should not include gynecological examinations or similar forms of invasive physical examinations, aimed at determining an athlete’s sex, sex variations or gender.” See Int’l Olympic Comm., supra, at 5. 18 Most states that have instituted categorical bans on transgender participation in student athletics have verified sex via a student’s birth certificate. Oklahoma and

49 offered any “exceedingly persuasive justification” warranting the imposition of this

objectively degrading and disturbing process on young women and girls who

participate in female athletics.

We must “reject measures that classify unnecessarily and overbroadly by

gender when more accurate and impartial lines can be drawn.” Sessions v.

Morales-Santana, 137 582 U.S. 47, 63 n.13 (2017). While the Act purports to

further athletic opportunities for Idaho’s female students, the district court

correctly concluded that the Act does not further this goal, and in fact “appears

unrelated to the interests the Act purportedly advances.” Hecox I, 470 F. Supp. 3d

at 979. And “[i]ntentional discrimination on the basis of gender by state action

violates the Equal Protection Clause[] where, as here, the discrimination serves to

ratify and perpetuate invidious, archaic, and overbroad stereotypes.” J.E.B. v.

Alabama ex rel. T.B., 511 U.S. 127, 131 (1994). Thus, we need not and do not

decide what policy would justify the exclusion of transgender women and girls

from Idaho athletics under the Equal Protection Clause, because the profound lack

of means-end fit here demonstrates that the Act likely does not survive heightened

scrutiny.

B. Irreparable Harm

Kentucky require a student or a student’s parent or legal guardian submit sworn affidavits to confirm their “biological sex.” See Okla. Stat. Ann. tit. 70, § 27- 106(D); Ky. Rev. Stat. Ann. § 164.2813(2).

50 The district court properly concluded that Lindsay faced irreparable harm

absent an injunction. “It is well established that the deprivation of constitutional

rights unquestionably constitutes irreparable injury.” Hernandez v. Sessions, 872

F.3d 976, 994 (9th Cir. 2017) (internal quotation marks and citation omitted).

Therefore, as the Act is likely unconstitutional, “it follows inexorably . . . that

[Hecox] ha[s] [] carried [her] burden as to irreparable harm.” Id. at 995.

More concretely, if the preliminary injunction is lifted, Lindsay will be

barred from trying out for or participating on any women’s sports at BSU,

including the women’s club soccer team, which she joined to improve her running

skills and experience “the camaraderie of being on a team.” See Idaho Code § 33-

6203(3). Lindsay would also be subject to the threat of the sex dispute verification

process and unnecessary examinations or medical testing. These are all specific

“harm[s] for which there is no adequate legal remedy” in the absence of an

injunction. Ariz. Dream Act Coal. v. Brewer, 757 F.3d 1053, 1068 (9th Cir. 2014).

C. Balance of the Equities & Public Interest

The district court also did not err in concluding that the balance of the

equities weighed in favor of a preliminary injunction. The third and fourth

preliminary injunction factors—assessing the harm to the opposing party and

weighing the public interest—merge where, as here, the government is the

opposing party. Nken, 556 U.S. at 435. Here, Lindsay faces deeply personal,

51 irreparable harms without injunctive relief, including being barred from all female

college athletic teams and the prospect of invasive medical testing if her gender is

“disputed.”

The preliminary injunction does not appear to inflict any comparable harm

on the Appellants. Under the pre-Act status quo, the NCAA policies for college

athletics and the IHSAA policies for high school athletics govern transgender

female participation in sports, and Idaho schools have complied with those policies

for over a decade. The district court found no “evidence that transgender women

threatened equality in sports, girls’ athletic opportunities, or girls’ access to

scholarships in Idaho” during that decade, and thus Appellants failed to

demonstrate any harm from issuance of the injunction. Hecox I, 479 F. Supp. 3d at

988. Moreover, as the district court found, Intervenors themselves may also be

harmed by the sex dispute verification process, to which they are subject simply by

virtue of playing sports in Idaho. Because “the public interest and the balance of

the equities favor preven[ting] the violation of a party’s constitutional rights,” Ariz.

Dream Act, 757 F.3d at 1060 (alteration in original) (internal quotation marks and

citation omitted), we affirm that the district court did not abuse its discretion in

weighing this factor.

IV. SCOPE OF THE INJUNCTION

52 Although we agree with the district court that the Act harms “not just the

constitutional rights of transgender girls and women athletes . . . [but also] the

constitutional rights of every girl and woman athlete in Idaho,” we remand to the

district court to clarify the scope of the preliminary injunction. Hecox I, 479 F.

Supp. 3d at 988. “A district court has considerable discretion in fashioning

suitable relief and defining the terms of an injunction,” and “[a]ppellate review of

those terms ‘is correspondingly narrow.’” Lamb-Weston, Inc. v. McCain Foods,

Ltd., 941 F.2d 970, 974 (9th Cir. 1991) (quoting Coca-Cola Co. v. Overland, Inc.,

692 F.2d 1250, 1256 n.16 (9th Cir.1982)). However, injunctive relief “must be

tailored to remedy the specific harm alleged,” and “[a]n overbroad injunction is an

abuse of discretion.” Id. (finding that a worldwide injunction to protect a trade

secret was not an abuse of discretion). Under Federal Rule of Civil Procedure Rule

65(d)(1), “[e]very order granting an injunction . . . must: (A) state the reasons why

it issued; (B) state its terms specifically; and (C) describe in reasonable detail—and

not by referring to the complaint or other document—the act or acts restrained or

required.”

Here, the scope of the injunction is not clear. Although the district court

granted Plaintiffs’ motion for preliminary injunction, the court’s order does not

specify whether enforcement of the Act is enjoined in whole or in part, nor does it

specify whether enforcement of the Act is enjoined facially or as applied to

53 particular persons. See Hecox I, 479 F. Supp. 3d at 988. On remand, the district

court should tailor the injunction to provide the specificity that Rule 65(d)(1)

requires.

We do not agree with the Intervenors, however, that the preliminary

injunction would necessarily be overbroad as a matter of law if it extends to

nonparties despite the district court’s dismissal of Lindsay’s facial challenge.

“[A]n injunction ‘should be no more burdensome to the defendant than necessary

to provide complete relief to the plaintiffs before the court.’” City & County of San

Francisco v. Barr, 965 F.3d 753, 765 (9th Cir. 2020) (quoting L.A. Haven Hospice,

Inc. v. Sebelius, 638 F.3d 644, 664 (9th Cir. 2011)). “[B]ut there is ‘no general

requirement that an injunction affect only the parties in the suit.’” East Bay

Sanctuary Covenant, 993 F.3d 640, 680 (9th Cir. 2021) (quoting Bresgal v. Brock,

843 F.2d 1163, 1169–1170 (9th Cir. 1987). Rather, “[t]he equitable relief granted

by the district court is acceptable where it is necessary to give prevailing parties

the relief to which they are entitled.” Id. (quotation marks omitted). Before

deciding whether it can accord Lindsay complete relief without enjoining the Act

in part or in whole as to all female student athletes in Idaho, the district court

should consider the effect, if any, of the Supreme Court’s decision in Labrador v.

Poe, 144 S. Ct. 921 (2024).

54 While we address only the Act before us, and opine on no other regulation or

policy, we must observe that both the science and the regulatory framework

surrounding issues of transgender women’s participation in female-designated

sports is rapidly evolving. Since Lindsay filed her initial challenge, the IOC and

NCAA have adopted more limited policies as to transgender female participation

in women’s sports, requiring the governing entities for each sport to formulate

sport-specific policies. Relying on medical evidence, many sports organizations

have tightened their eligibility criteria for transgender women’s teams, including

incorporating guidelines for lower testosterone levels for eligibility to compete.19

The U.S. Department of Education has proposed new Title IX regulations

addressing restrictions on transgender athletes’ eligibility that would require “such

criteria” to “be substantially related to the achievement of an important educational

objective and minimize harms to students whose opportunity to participate on a

19 See, e.g., USA Swimming, USA Swimming Releases Athlete Inclusion, Competitive Equity and Eligibility Policy (Feb. 1, 2022), https://tinyurl.com/mr2k4tvp (announcing a policy for USA Swimming that elite transgender women athletes must show testosterone levels below 5 nmol/L continuously for at least 36 months); Bicycling, The UCI Announces Changes to Its Policy on Transgender Athletes (June 17, 2022), https://www.bicycling.com/news/a40320907/uci-transgender-policy-2022/ (announcing a testosterone limit of 2.5 nmol/L for elite bicyclists (halved from the previous 5.0 nmol/L) for a suppression period of 24 months); Olalla Cernuda, World Triathlon Executive Board approves Transgender Policy, World Triathlon (Aug. 3, 2022), https://tinyurl.com/yxw4syzw (requiring below a 2.5 nmol/L testosterone level for 24 months for triathletes).

55 male or female team consistent with their gender identity would be limited or

denied.”20 These more narrowly drawn policies, which are not before us, attempt

to balance transgender inclusion with competitive fairness—a policy question that

such regulatory bodies are best equipped to address.

VI. CONCLUSION

We recognize that, after decades of women being denied opportunities to

meaningfully participate in athletics in this country, many cisgender women

athletes reasonably fear being shut out of competition because of transgender

athletes who “retain an insurmountable athletic advantage over cisgender women.”

See Br. of Amici Curiae Sandra Bucha, et al. at 8. We also recognize that athletic

participation confers on students not just an opportunity to win championships and

scholarships, but also the benefits of shared community, teamwork, leadership, and

discipline. See generally Br. of Amici Curiae 176 Athletes in Women’s Sports

(describing the benefits of sports, and diversity in women’s sports, on all students).

Excluding transgender youth from sports necessarily means that some transgender

youth will be denied those educational benefits.

20 Nondiscrimination on the Basis of Sex in Education Programs or Activities Receiving Federal Financial Assistance: Sex-Related Eligibility Criteria for Male and Female Athletic Teams, 88 Fed. Reg. 22860 (proposed April 13, 2023) (to be codified at 34 C.F.R. pt. 106).

56 However, we need not and do not decide the larger question of whether any

restriction on transgender participation in sports violates equal protection.

Heightened scrutiny analysis is an extraordinarily fact-bound test, and today we

simply decide the narrow question of whether the district court, on the record

before it, abused its discretion in finding that Lindsay was likely to succeed on the

merits of her equal protection claim. Because it did not, we affirm the district

court’s order granting preliminary injunctive relief as applied to Lindsay, vacate

the injunction as applied to non-parties, and remand to the district court to address

the scope and clarity of the injunction.

AFFIRMED IN PART; VACATED IN PART; REMANDED.