POSNER, Circuit Judge!
The government appeals from an order by the district court quashing a subpoena commanding Northwestern Memorial Hospital in Chicago to produce the medical records of certain patients on whom Dr. Cassing Hammond had performed late-term abortions at the hospital using the controversial method known variously as “D & X” (dilation and extraction) and “intact D & E” (dilation and evacuation). We accelerated briefing and argument, and now accelerate our decision, in view of the pressures of time discussed later in the opinion.
The subpoenaed records, apparently some 45 in number, are sought for use'in the forthcoming trial in the Southern District of New York of a suit challenging the constitutionality of the Partial-Birth Abortion Ban Act of 2003, Pub.L. No. 108-105, 117 Stat. 1201, 18 U.S.C. § 1531. See National Abortion Federation v. Ashcroft, 2004 WL 540470 (S.D.N.Y. Mar.17, 2004) (order denying summary judgment for plaintiffs). Dr. Hammond is one of the plaintiffs in that suit and will also be testifying as an expert witness. The district court held that the production of the records is barred by regulations issued under the Health Insurance Portability and Accountability Act of 1996 (HIPAA), Pub.L. 104-191, 110 Stat. 1936, and let us begin there.
Section 264 of HIPAA, 42 U.S.C. § 1320d-2 Note, directs the Secretary of Health and Human Services to promulgate regulations to protect the privacy of medical records, but provides in subsection (c)(2) that such a regulation “shall not supercede a contrary provision of State law, if the provision of State law imposes requirements, standards, or implementation specifications that are more stringent than the requirements, standards, or implementation specifications imposed under the regulation.” See also 45 C.F.R. § 160.203(b). A standard is “more stringent” if it “provides greater privacy protection for the individual who is the subject of the individually identifiable health information” than the standard in the regulation. § 160.202(6).
The particular focus of the appeal is an HHS regulation entitled “Standard: Disclosures for Judicial and Administrative [925]*925Proceedings,” § 164.512(e), which authorizes a “covered entity” (such as Northwestern Memorial Hospital) to disclose private health information in judicial or administrative proceedings “in response to an order of a court.” § 164.512(e)(1)(f). The regulation also allows the disclosure of such information in those proceedings “in response to a subpoena, discovery request, or other lawful process,” § 164.512(e)(l)(ii), if the party seeking the information either notifies the patient (or at least makes a good faith effort to do so) or makes a “reasonable effort” to secure a qualified protective order, that is, an order that prohibits the use or disclosure of the information outside the litigation and requires the return or destruction of the information at the end of the litigation. 45 C.F.R. § 164.512(e)(l)(v).
The district judge presiding over the case in New York issued an order authorizing, although not directing, the hospital to provide the records to the government after redaction to remove information identifying the patients. The parties agree that his order is an “order” within the meaning of the “in response” provision. It hardly matters; the government didn’t need such an order because it had obtained a protective order, thus qualifying under the alternative procedure for disclosure of medical records. But under Illinois law, even redacted medical records are not to be disclosed in judicial proceedings, with immaterial exceptions. 735 ILCS 5/8-802; Department of Professional Regulation v. Manos, 326 Ill.App.3d 698, 260 Ill.Dec. 364, 761 N.E.2d 208, 216-17 (2001); Parkson v. Central DuPage Hospital, 105 Ill.App.3d 850, 61 Ill.Dec. 651, 435 N.E.2d 140, 143-44 (1982). The district court in our case ruled that the Illinois law, because it sets a “more stringent” standard for disclosure than- the HI-PAA regulation, trumps that regulation by virtue of HIPAA’s supersession provision. So he quashed the subpoena, precipitating this appeal.
Although the issue is not free from doubt, we agree with the government that the HIPAA regulations do not impose state evidentiary privileges on suits to enforce federal law. Illinois is free to enforce its more stringent medical-records privilege (there is no comparable federal privilege) in suits in state court to enforce state law and, by virtue of an express provision in Fed.R.Evid. 501, in suits in federal court (mainly diversity suits) as well in which state law supplies the rule of decision. But the Illinois privilege does not govern in federal-question suits, such as the suit in the Southern District of New York. The enforcement of federal law might be hamstrung if state-law privileges more stringent than any federal privilege regarding medical records were applicable to all federal cases. We say “might” not “would” because some federal statutes authorize subpoenas in terms that would override the HIPAA regulations. See, e.g., 18 U.S.C. § 3486; In re Subpoena Duces Tecum, 228 F.3d 341 (4th Cir.2000). But almost certainly there are gaps; and we think it improbable that HHS intended to open such a can of worms when it set forth a procedure for disclosure of medical records in litigation — intended, that is, to be regulating, actually or potentially (depending on other statutory provisions regulating subpoenas), the litigation of federal employment discrimination cases, social security disability cases, ERISA cases, Medicare and Medicaid fraud cases, Food and Drug Administration cases; and the numerous other classes of federal case in which medical records whether of the parties or of nonparties would not be privileged under federal evidence law.
All- that 45 C.F.R. § 164.512(e) should be understood to do, therefore, is to [926]*926create a procedure for obtaining authority to use medical records in litigation. Whether the records are actually admissible in evidence will depend among other things on whether they are privileged. And the evidentiary privileges that are applicable to federal-question suits are given not by state law but by federal law, Fed.R.Evid. 501, which does not recognize a physician-patient (or hospital-patient) privilege. Rule 501 in terms makes federal common law the source of any privileges in federal-question suits unless an Act of Congress provides otherwise. We do not think HIPAA is rightly understood as an Act of Congress that creates a privilege.
The purely procedural character of the HIPAA standard for disclosure of medical information in judicial or administrative proceedings is indicated by the procedure for disclosure in response to a subpoena or other process; the notice to the patient must contain “sufficient information about the litigation or proceeding in which the protected health information is requested to permit the individual to raise an objection to the court.” § 164.512(e)(l)(iii)(B). The objection in court would often be based on a privilege — the source of which would be found elsewhere than in the regulations themselves.
This conclusion is buttressed by a HI-PAA regulation which says that the “more stringent” clause applies only to “individually identifiable health information,” § 160.203(b), as opposed to “health information that does not identify an individual and with respect to which there is no reasonable basis to believe that the information can be used to identify an individual.” § 164.514(a). Provided that medical records are redacted in accordance with the redaction requirements (themselves quite stringent) of § 164.514(a), they would not contain “individually identifiable health information” and the “more stringent” clause would fall away.
As an alternative basis for quashing the subpoena, the district judge undertook to craft a new federal common law privilege for abortion records. He based this ruling on their sensitivity, which he compared to that of psychotherapists’ treatment records, held privileged in Jaffee v. Redmond, 518 U.S. 1, 116 S.Ct. 1923, 135 L.Ed.2d 337 (1996). The creation of new common law evidentiary privileges is authorized by Fed.R.Evid. 501, and Jaffee is not the only recent case in which the authority was exercised. Goodyear Tire & Rubber Co. v. Chiles Power Supply, Inc., 332 F.3d 976, 979-81 (6th Cir.2003); In re Air Crash Near Cali, Colombia, 959 F.Supp. 1529, 1533-35 (S.D.Fla.1997), and United States v. Lowe, 948 F.Supp. 97, 99-100 (D.Mass.1996), all created new privileges on the authority of Jaffee. But none relates to medical records and we are reluctant to embark on a case-by-case determination of the relative sensitivity of medical records of different ailments or procedures. Most medical records are sensitive, and many are as sensitive as late-term abortion records, such as the records of AIDS patients. Proceeding down the path taken by the district court would inevitably result in either arbitrary line drawing or the creation of an Illinois-type comprehensive privilege for medical records. Northwestern Memorial Hospital concedes that there is no federal common law physician-patient privilege. It is not for us — especially in so summary a proceeding as this litigation to quash the government’s subpoena- — -to create one, whether all at once or by a process of slow but inevitable additions to the sole category recognized by Jaffee. Cf. University of Pennsylvania v. EEOC, 493 U.S. 182, 188-89, 110 S.Ct. 577, 107 L.Ed.2d 571 (1990); United [927]*927States v. Nixon, 418 U.S. 683, 707-13, 94 S.Ct. 3090, 41 L.Ed.2d 1039 (1974); In re Witness Before Special Grand, Jury 2000-2, 288 F.3d 289 (7th Cir.2002); In re Sealed Case, 148 F.3d 1073, 1078-79 (D.C.Cir.1998) (per curiam).
The district court did not reach a further ground urged by Northwestern Memorial Hospital for quashing the government’s subpoena, which is simply that the burden of compliance with it would exceed the benefit of production of the material sought by it. Fed.R.Civ.P. 45(c)(3)(A)(iv); Deitchman v. E.R. Squibb & Sons, Inc., 740 F.2d 556, 563 (7th Cir.1984); Roberts v. Shawnee Mission Ford, Inc., 352 F.3d 358, 361-62 (8th Cir.2003); Miscellaneous Docket Matter # 1. v. Miscellaneous Docket Matter # 2, 197 F.3d 922, 926-27 (8th Cir.1999); In re Sealed Case, 162 F.3d 670, 673-74 (D.C.Cir,1998). However, in support of his ruling expanding the federal common law of privilege to embrace the medical records of abortion patients, the judge made findings that are highly germane to — indeed arguably dis-positive of — the Rule 45(c) issue. He pointed out that the “government seeks these records on the possibility that it may find something therein which would affect the testimony of Dr. Hammond adversely, that is, for its potential value in impeaching his credibility as a witness. What the government ignores in its argument is how little, if any, probative value lies within these patient records.” He contrasted the dearth of probative value “with the potential loss of privacy that would ensue were these medical records used in a case in which the patient was not a party” and concluded that “the balance of harms resulting from disclosure severely out-weighs the loss to the government through non-disclosure.”
These findings were solidly based. The hospital had urged both the lack of probative value of the records and the loss of privacy by the patients. The government had responded in generalities, arguing that redaction would eliminate any privacy concern and that since Dr. Hammond had “made assertions of fact about his experience and his patients that plaintiffs are using to support their claim that, without a health exception, the Act is unconstitutional,” the government should be permitted to test those assertions; but the government had not indicated what assertions these were or how the records might bear on them. Although on appeal the hospital repeated at length its reasons for believing that the records sought by the government would have little or no probative value, the government’s response in both its opening-brief and its reply brief remained vague to the point of being evasive.
At the oral argument we pressed the government’s lawyer repeatedly and hard for indications of what he hoped to learn from the hospital records, and drew a blank. (Contrary to our usual practice, we did not limit the length of the oral argument.) The lawyer did suggest that if Hammond testified that patients with leukemia are better off with the D & X procedure than with the conventional D & E procedure but the medical records indicate that not all abortion patients with leukemia undergo D & X abortions, this would both impeach Hammond and suggest that D & X is not the only medically safe abortion procedure available to pregnant women afflicted with leukemia. But such information would be unlikely to be found in Hammond’s records, given his strongly expressed preference for using the D & X method in the case of patients in fragile health. The information would be much more likely to be found in the records of physicians who perform D & E rather than D & X abortions on such [928]*928women. Those records, however, the government didn’t seek.
We learned at argument for the first time that Dr. Hammond has been deposed in the New York litigation. The questions and answers in his deposition might illuminate the relevance of the medical records for impeachment of his testimony at the trial. But the government has made no effort to make the deposition a part of the record.
Ordinarily when a district judge has not addressed an issue committed to his discretion, such as the balance of benefit and burden in complying with a subpoena, e.g., Peate v. McCann, 294 F.3d 879, 884 (7th Cir.2002); Deitchman v. E.R. Squibb & Sons, Inc., supra, 740 F.2d at 563; Pamida, Inc. v. E.S. Originals, Inc., 281 F.3d 726, 729 (8th Cir.2002), and the issue becomes critical to the disposition of the appeal, the appellate court must remand to give the judge a chance to exercise his discretion. Icicle Seafoods, Inc. v. Worthington, 475 U.S. 709, 106 S.Ct. 1527, 89 L.Ed.2d 739 (1986). We do not follow that course, here, however, for two reasons. The first is that the judge, in the passages we quoted from his opinion, struck the balance — in other words, “weighted the] competing hardships.” Deitchman v. E.R. Squibb & Sons, Inc., supra, 740 F.2d at 563. True, he did so in the course of addressing a different issue from whether Rule 45(c) required that the subpoena be quashed; but, realistically, the result of a remand is foreordained.
The second reason is that with the trial in New York scheduled to begin on March 29 and to last only four weeks, the practical effect of a remand would be to moot the issue of compliance with the subpoena. The time factor is unfortunate, and is not the fault of the government (or of anyone else, so far as appears). If time permitted a remand, the judge would on remand examine the records, or at least a sample of them, in camera, as in the parallel subpoena case of Planned Parenthood Federation of America, Inc. v. Ashcroft, 2004 WL 432222 (N.D.Cal. Mar.5, 2004), to determine whether they are likely to have any probative value. Time does not permit. The government has not suggested that the case be remanded if we reject the district court’s grounds for quashing the subpoena. A remand would be tantamount to mooting its appeal; in the government’s words, “a remand would entirely frustrate the Government’s interest in preparing a timely defense in the New York trial, which will begin on March 29.” We take this as a waiver of any objection to our weighing the hardships ourselves, and we proceed to the weighing. See Beer Nuts, Inc. v. Clover Club Foods Co., 805 F.2d 920, 923 n. 2 (10th Cir.1986); McCord v. Bailey, 636 F.2d 606, 613 (D.C.Cir.1980); cf. International Ins. Co. v. Caja Nacional De Ahorro y Seguro, 293 F.3d 392, 401 (7th Cir.2002); Dillard v. City of Greensboro, 213 F.3d 1347, 1355-57 (11th Cir.2000).
Like the district judge, we think the balance weighs in favor of quashing the subpoena. The government does not deny that the hospital is an appropriate representative of the privacy interests of its patients. Parkson v. Central DuPage Hospital, supra, 61 Ill.Dec. 651, 435 N.E.2d at 142. But it argues that since it is seeking only a limited number of records and they would be produced to it minus the information that would enable the identity of the patient to be determined, there is no hardship to either the hospital or the patients of compliance. The argument is unrealistic and incomplete. What is true is that the administrative hardship from compliance would be modest. But it is not the only or the main hardship. The natural sensitivity that [929]*929people feel about the disclosure of their medical records — the sensitivity that lies behind HIPAA — is amplified when the records are of a procedure that Congress has now declared to be a crime. Even if all the women whose records the government seeks know what “redacted” means, they are bound to be skeptical that redaction will conceal their identity from the world. This is hardly a typical case in which medical records get drawn into a lawsuit. Reflecting the fierce emotions that the long-running controversy over the morality and legality of abortion has made combustible, the Partial-Birth Abortion Ban Act and the litigation challenging its constitutionality — and even more so the rash of suits around the country in which the Department of Justice has been seeking the hospital records of abortion patients — have generated enormous publicity. These women must know that, and doubtless they are also aware that hostility to abortion has at times erupted into violence, including criminal obstruction of entry into abortion climes, the firebombing of clinics, and the assassination of physicians who perform abortions.
Some of these women will be afraid that when their redacted records are made a part of the trial record in New York, persons of their acquaintance, or skillful “Goo-glers,” sifting the information contained in the medical records concerning each patient’s medical and sex history, will put two and two together, “out” the 45 women, and thereby expose them to threats, humiliation, and obloquy. As the court pointed out in Parkson v. Central DuPage Hospital, supra, 61 Ill.Dec. 651, 435 N.E.2d at 144, “whether the patients’ identities would remain confidential by the exclusion of their names and identifying numbers is questionable at best. The patients’ admit and discharge summaries arguably contain histories of the patients’ prior and present medical conditions, information that in the cumulative can make the possibility of recognition very high.” In its opening brief, as throughout the district court proceeding, the government expressly reserved the right, at a later date, to seek the identity of the patients whose records are produced. Pressed at argument, the government’s lawyer abandoned the reservation; but we do not know what would prevent reconsideration should the government, the subpoena having been enforced, discover that particular medical records that it had obtained were incomplete, opaque, or ambiguous.
Even if there were no possibility that a patient’s identity might be learned from a redacted medical record, there would be an invasion of privacy. Imagine if nude pictures of a woman, uploaded to the Internet without her consent though without identifying her by name, were downloaded in a foreign country by people who will never meet her. She would still feel that her privacy had been invaded. The revelation of the intimate details contained in the record of a late-term abortion may inflict a similar wound.
If Northwestern Memorial Hospital cannot shield the medical records of its abortion patients from disclosure in judicial proceedings, moreover, the hospital will lose the confidence of its patients, and persons with sensitive medical conditions may be inclined to turn elsewhere for medical treatment. It is not as if the government were seeking medical records from every hospital and clinic that performs late-term abortions, in which event women wanting assurance against the disclosure of their records would have nowhere to turn. It is Dr. Hammond’s presence in the New York suit as plaintiff and expert that has resulted in the government’s subpoenaing Northwestern Memorial Hospital.
[930]*930The concerns that the hospital has articulated do not necessarily justify withholding probative evidence from the government; nor can the possibility that medical records of abortion patients would yield evidence germane to the constitutionality of the Partial-Birth Abortion Ban Act be gainsaid. A nearly identical state predecessor of the Act was invalidated by the Supreme Court in Stenberg v. Carhart, 530 U.S. 914, 120 S.Ct. 2597, 147 L.Ed.2d 743 (2000), because it did not permit the D & X procedure in cases in which it is required to protect the health of the pregnant woman. Id. at 930-38, 120 S.Ct. 2597. In response, the preamble to the Act contains a finding that the procedure is never required for health reasons. 117 Stat. 1201, § 2. The government concedes as it must that this finding, although entitled to respectful consideration, does not bind the courts. E.g., United States v. Morrison, 529 U.S. 598, 614, 120 S.Ct. 1740, 146 L.Ed.2d 658 (2000); Turner Broadcasting System, Inc. v. FCC, 512 U.S. 622, 665-66, 114 S.Ct. 2445, 129 L.Ed.2d 497 (1994) (plurality). The issue of medical necessity remains for determination at the trial in New York, where Dr. Hammond will testify that he believes there are situations in which the D & X procedure is medically indicated. The essential difference between that procedure and the conventional D & E procedure is that in the latter procedure the fetus is destroyed while it is still entirely within the womb, while in the former procedure it is destroyed after the lower extremities, and sometimes the torso, have emerged from the womb and only the head remains inside. It is because part of the fetus is outside the womb when the fetus is destroyed that the supporters of the Act describe the D & X procedure as “partial birth” abortion. Dr. Hammond and other D & X practitioners argue that because less of the fetus is in the womb there is less danger of cutting the woman’s tissues with the sharp knives used to dismember the fetus’s body in the conventional D & E procedure and causing hemorrhaging, and that if the woman is in fragile health avoiding that danger is medically indicated.
The merits of the dispute are for determination at trial. The only issue for us is whether, given that there is a potential psychological cost to the hospital’s patients, and a potential cost in lost goodwill to the hospital itself, from the involuntary production of the medical records even as redacted, the cost is offset by the probative value of the records. The district judge presiding at the trial has said that the records are “relevant,” and no doubt they are — in the attenuated sense in which non-privileged materials may be sought in discovery. “Relevant information need not be admissible at the trial if the discovery appears reasonably calculated to lead to the discovery of admissible evidence.” Fed.R.Civ.P. 26(b)(1); see Oppenheimer Fund, Inc. v. Sanders, 437 U.S. 340, 350-52, 98 S.Ct. 2380, 57 L.Ed.2d 253 (1978); CSC Holdings, Inc. v. Redisi, 309 F.3d 988, 995-96 (7th Cir.2002). The trial judge has not opined on the probative value of the records, which appears to be meager.
The government has had repeated opportunities to articulate a use for the records that it seeks, and it has failed to do so. What it would like to prove at the trial in New York, to refute Dr. Hammond, is that D & E is always an adequate alternative, from the standpoint of a pregnant woman’s health, to the D & X procedure. But the government has failed to explain how the record of a D & X abortion would show this. And it is not as if-Hammond had relied on the medical records of his patients in preparing his expert testimony. (Had he done so, they would have had to be disclosed to the government under Fed. R.Civ.P. 26(a)(2).) He doesn’t have the [931]*931records, is not basing his testimony on them, and so far as appears doesn’t even remember, them.
None of the records is going to state that Dr. Hammond said that he performed a D & X although he believed that a D & E would be just as good. We thought the government might be hoping to find in the records evidence that Hammond had lied when he said he had performed a D & X on a woman who had leukemia or a woman who had breast cancer, but at argument the government disclaimed any such suggestion. We’re still at a loss to understand what it hopes to gain from such discovery. (We begged the government’s lawyer to be concrete.) Of course, not having seen the records, the government labors under a disadvantage, although it has surely seen other medical records. And of course, pretrial discovery is a fishing expedition and one can’t know what one has caught until one fishes. But Fed. R.Civ.P. 45(c) allows the fish to object, and when they do so the fisherman has to come up with more than the government has been able to do in this case despite the excellence of its lawyers. ,
The Partial-Birth Abortion Ban Act was passed, as we said, in response to the Supreme Court’s decision in the Stenberg case. Stenberg was one of a number of “first generation” partial-birth cases. The others were Hope Clinic v. Ryan, 195 F.3d 857 (7th Cir.1999) (en banc); Planned Parenthood of Wisconsin v. Doyle, 162 F.3d 463 (7th Cir.1998); Planned Parenthood of Greater Iowa, Inc. v. Miller, 195 F.3d 386 (8th Cir.1999); Little Rock Family Planning Services, P.A. v. Jegley, 192 F.3d 794 (8th Cir.1999); Summit Medical Associates, P.C. v. Pryor, 180 F.3d 1326 (11th Cir.1999); Richmond Medical Center for Women v. Gilmore, 144 F.3d 326 (4th Cir.1998); Women’s Medical Professional Corp. v. Voinovich, 130 F.3d 187 (6th Cir.1997); Armstrong v. State, 296 Mont. 361, 989 P.2d 364 (1999); WomanCare of Southfield, P.C. v. Granholm, 143 F.Supp.2d 827 (E.D.Mich.2000); Rhode Island Medical Soc. v. Whitehouse, 66 F.Supp.2d 288 (D.R.I.1999), affirmed, 239 F.3d 104 (1st Cir.2001) (per curiam); Richmond Medical Center for Women v. Gilmore, 55 F.Supp.2d 441 (E.D.Va.1999), affirmed, 224 F.3d 337 (4th Cir.2000) (per curiam); Causeway Medical Suite v. Foster, 43 F.Supp.2d 604 (E.D.La.1999), affirmed, 221 F.3d 811 (5th Cir.2000); A Choice for Women v. Butterworth, 54 F.Supp.2d 1148 (S.D.Fla.1998); Planned Parenthood of Central New Jersey v. Verniero, 22 F.Supp.2d 331 (D.N.J.1998); Planned Parenthood of Central New Jersey v. Verniero, 41 F.Supp.2d 478 (D.N.J.1998), affirmed, 220 F.3d 127 (3d Cir.2000); Eubanks v. Stengel, 28 F.Supp.2d 1024 (W.D.Ky.1998), affirmed, 224 F.3d 576 (6th Cir.2000) (per curiam); Midtown Hospital v. Miller, 36 F.Supp.2d 1360 (N.D.Ga.1997); Planned Parenthood of Southern Arizona, Inc. v. Woods, 982 F.Supp. 1369 (D.Ariz.1997); Evans v. Kelley, 977 F.Supp. 1283 (E.D.Mich.1997). In one of the cases decided by this court, Hope Clinic v. Ryan, supra, Dr. Hammond was both a plaintiff and an expert witness. Hope Clinic v. Ryan, 995 F.Supp. 847, 849-850 (N.D.Ill.1998). Yet in none of these many cases, so far as either we or the government is aware, was it so much as suggested that patient records might contain information that would help answer the question, crucial then as now, whether the D & X procedure is ever medically necessary.
Although Hammond is a plaintiff in the New York case, presumably because he actually performs D & X abortions and wants to be allowed to continue doing so, he will be testifying as an expert medical witness. Of all experts who testify in court, physicians are probably the most [932]*932common. Yet the government has cited to us no case before this one in which medical experts’ patient records were used to impeach the expert (Langley v. Coughlin, 1989 WL 436675 (S.D.N.Y. June 19, 1989), rejected the attempt, in a helpful discussion), though in malpractice eases it is not uncommon to use redacted medical records bearing on the defendant’s alleged negligence for impeachment, as in Terre Haute Regional Hospital, Inc. v. Trueblood, 600 N.E.2d 1358 (Ind.1992), and Todd v. South Jersey Hospital System, 152 F.R.D. 676, 684-85 (D.N.J.1993).
Were the government sincerely interested in whether D & X abortions are ever medically indicated, one would have expected it to seek from Northwestern Memorial Hospital statistics summarizing the hospital’s experience with late-term abortions. Suppose the patients who undergo D & X abortions are identical in all material respects (age, health, number of weeks pregnant, and so on) to those who undergo procedures not forbidden by the Partial-Birth Abortion Ban Act. That would be potent evidence that the D & X procedure does not have a compelling health rationale. No such evidence has been sought, in contrast to Planned Parenthood Federation of America, Inc. v. Ashcroft, supra, at Transcript 26 (Mar. 5, 2004). A variant of the suggested approach would be to obtain a random sample of late-term abortion records from various sources and then determine, through good statistical analysis, whether the patient characteristics that lead Dr. Hammond to perform a D & X lead other physicians to perform a conventional D & E instead, and whether there are differences in the health consequences for these two groups of women. If there are no differences, the government might have a good defense of the Act. Gathering records from Hammond’s patients alone will not be useful; but if the government has other records (say, from VA hospitals) already in its files, then records of Hammond’s procedures might enable a useful comparison. The government hasn’t suggested doing anything like that either. Its motives in seeking individuals’ medical records remain thoroughly obscure.
The question whether the D & X procedure is ever medically indicated will be resolved as a matter of legislative fact not requiring the taking of trial-type testimony at all (see Hope Clinic v. Ryan, supra, 195 F.3d at 885 (dissenting opinion)), or will pivot on the clash of expert witnesses at the New York trial, or perhaps, as suggested in Stenberg, will be answered by some combination of these two approaches to ascertaining facts. The medical records of expert witnesses are irrelevant to the first inquiry; and, so far as we can determine after having listened to the government’s arguments at length, those records will not figure significantly in the resolution of experts’ disagreements either.
The fact that quashing the subpoena comports with Illinois’ medical-records privilege is a final factor in favor of the district order’s action. As we held in Memorial Hospital for McHenry County v. Shadur, 664 F.2d 1058, 1061 (7th Cir.1981), comity “impels federal courts to recognize state privileges where this can be accomplished at no substantial cost to federal substantive and procedural policy.” See also United States v. One Parcel of Property Located at 31-33 York Street, 930 F.2d 139, 141 (2d Cir.1991) (per curiam). Patients, physicians, and hospitals in Illinois rely on Illinois’ strong policy of privacy of medical records. They cannot rely completely, for they are not entitled to count on the state privilege’s being applied in federal court. But in a case such as this in which, so far as we can determine, applying the privilege would not interfere significantly with federal proceedings, [933]*933comity has required us not to apply the Illinois privilege, but to consider with special care the arguments for quashing the subpoena on the basis of relative hardship under Fed.R.Civ.P. 45(c).
AFFIRMED.