[576]*576HUGHES, J.
_[jThis writ presents the issue of whether an alleged biological father should be joined in a child support enforcement action, filed pursuant to LSA-R.S. 46:236.1.1 et seq. against the legally-presumed father. The juvenile court denied joinder, and the appellate court denied writs. Concluding that a biological father owes an obligation of support to his child, we reverse and remand for further proceedings.
FACTS AND PROCEDURAL HISTORY
In December of 2002 Thomas Robert Lowrie married Melissa Percy Lowrie, who gave birth to two children during the marriage: A.L., born February 4, 2003; and B.W., born May 4, 2009. In October of 2010 the Lowries were divorced.
| a Although the children were born during the marriage, Mr. Lowrie, believing that Stephen A. Wetzel was the biological father of the children, sought to disavow paternity of the children. Mr. Lowrie successfully disavowed paternity of the younger child, B.W., in January of 2011; however, his action to disavow the older child, A.L., was found to be untimely. Therefore, Mr. Lowrie remains the legal father ofA.L.
In September of 2012, the State of Louisiana, Department of Children and Family Services (“DCFS”), represented by the Jefferson Parish District Attorney (collectively, “State”), filed an action in the Jefferson Parish Juvenile Court against Mr. Lowrie, seeking medical and child support for A.L. DCFS alleged that it was providing services for A.L., which created a cause of action in favor of the State pursuant to the State’s child support enforcement law, LSA-R.S. 46:236.1.1 et seq.
The court minutes for January 22, 2013 stated that both A.L.’s mother and Mr. Lowrie appeared, along with counsel, before the juvenile court hearing officer on a rule for child support.1 The hearing officer noted that “[tjhere is a biological father also [and] his income was imputed as $1919.00 from the Louisiana Occupational Handbook.” The minutes also noted that the hearing officer calculated what the proportional amount of child support for Mr. Lowrie would be if the combined monthly income for the parties included the attributed income of the biological father; the monthly amount owed by Mr. Lowrie when calculated by that method was $869.00. However, the minute entry further stated:
The hearing officer does not agree with the foregoing methodology and will not consider the income of the biological father in the calculation.
The hearing officer cannot proceed with the calculation of another worksheet as both parties may be benefitting from expense sharing and sufficient information is not available.
L[The] [h]earing officer recommends that [a] temporary order of support be entered in the amount of $500.00 ... every month.... [2]
[577]*577A judgment was thereafter signed by the juvenile court judge ordering that the recommendation of the hearing officer be made the judgment of the court.
On July 19, 2013, Mr. Lowrie filed a “Petition for Third Party Claim,” alleging that Mr. Wetzel was a necessary and indispensable party to the support proceeding, asserting that Mr. Wetzel’s income should be included in any child support calculation, and requesting that Mr. Wetzel be made a party defendant. In response, Mr. Wetzel filed exceptions of no cause of action, no right of action, lack of procedural capacity, and vagueness.
Following a December 9, 2013 review by the juvenile court hearing officer, the hearing officer recommended that Mr. Lowrie’s third party claim be dismissed, stating:
Thomas Robert Lowrie (original defendant herein) is the legal father of [A.L.], having been married to the mother of said child, Melissa Danielle Lowrie. Mr. Lowrie is listed as the child’s father on the birth certificate. A disavowal action has been dismissed as untimely.
Stephen A. Wetzel argues through counsel that he has not been found to be the biological father of [A.L.], and that the proper plaintiff in any filiation action is Melissa Danielle Lowrie, the recipient of child support herein, rather than the [DCFS]. Ms. Lowrie has not filed any action to have Mr. Wetzel named as the child’s biological father.
The hearing officer recommends that the Third Party Claim be dismissed as to Stephen A. Wetzel, as he has not been found to be the biological father of [A.L.] (or to have any official relationship to the child) and therefore has no obligation to provide support.
The attorney for Thomas Robert Lowrie disagrees and requests a hearing before the judge.
During the subsequent February 24, 2014 hearing before the juvenile court judge, Mr. Lowrie proffered into evidence Melissa Lowrie’s March 2013 answers |4to interrogatories, wherein she admitted that: Mr. Wetzel was the biological father of both B.W. and A.L.; Mr. Wetzel submitted to paternity testing for A.L.; the results of the paternity test reflected that Mr. Wet-zel was the biological father of A.L.; and, she was living with Mr. Wetzel. A copy of the 2008 “Paternity Analysis Report” was also proffered and filed into the juvenile court record; it stated that Mr. Wetzel’s probability of paternity of A.L. was 99.17%.3 The juvenile court judge ruled to uphold the hearing officer’s December 9, 2013 recommendation to dismiss Mr. Low-rie’s third party demand against Mr. Wet-zel.
Mr. Lowrie applied for supervisory review to the appellate court, which denied his application. See State, Department of Children and Family Services ex rel. A.L. v. Lowrie, 14-0210 (La.App. 5 Cir. 4/16/14) (unpublished). Mr. Lowrie then filed a writ application with this court, which was granted. See State, Department of Children and Family Services ex rel. A.L. v. Lowrie, 14-1025 (La.10/3/14), 149 So.3d 275.
LAW AND ANALYSIS
Third Party Demand
A demand incidental to the principal demand may be instituted against an [578]*578adverse party, a co-party, or against a third person. LSA-C.C.P. art. 1081(A). Incidental demands are reconvention, cross-claims, intervention, and the demand against third parties. LSA-C.C.P. art. 1031(B). The defendant in a principal action by petition may bring in any person, including a codefendant, who is his war-rantor, or who is or may be liable to him for all or part of the principal demand. LSA-C.C.P. art. 1111. In such cases the plaintiff in the principal action | Bmay assert any demand against the third party defendant arising out of or connected with the principal demand. Id.
However, the legislature did not intend that LSA-C.C.P. art. 1111 be used by a third party plaintiff to implead a third party defendant on the assertion that he is hable to the original plaintiff directly for all or part of the original plaintiffs demand. Article 1111 provides, rather, that the third party demand must allege that the third party defendant is liable to the third party plaintiff for all or part of the principal demand. See Karam v. St. Paul Fire & Marine Insurance Company, 281 So.2d 728, 732 (La.1973). When a third party plaintiff does not allege that the third party defendant is liable to them for all or part of the principal demand, the third party demand fails to state a cause of action. Id.
In this case, Mr. Lowrie’s “third party claim” against Mr. Wetzel did not assert that Mr. Wetzel was his warrantor or that Mr. Wetzel was liable to him for all or part of the principal demand; therefore, the claims asserted were not properly presented as a third party demand.
Nevertheless, our Code of Civil Procedure requires that every pleading be so construed as to do substantial justice. See LSA-C.C.P. art. 865. Further, the articles of the Code of Civil Procedure are to be construed liberally, and with due regard for the fact that rules of procedure implement the substantive law and are not an end in themselves. See LSA-C.C.P. art. 5051.
Harsh rules of pleading are not favored in this state. Each pleading must be reasonably construed so as to afford the litigant his day in court, arrive at the truth, and do substantial justice. Succession of Smith, 247 La. 921, 928, 175 So.2d 269, 271 (La.1965). See also Quinn v. Louisiana Citizens Property Insurance Corporation, 12-0152 (La.11/2/12), 118 So.3d 1011, 1017 n. 6; First National Bank of Picayune v. Pearl River Fabricators, Inc., 06-2195 (La.11/16/07), 971 So.2d 302, 308-09. The characterization of a pleading by the litigant is not | (¡controlling. Pleadings are taken for what they actually are and not for what their authors designate them. A court should not reject a justiciable cause “merely because it is dressed in the wrong coat.” Succession of Smith, 175 So.2d at 271. See also Alcorn v. City of Baton Rouge ex rel. Baton Rouge Police Department, 03-2682 (La.1/16/04), 863 So.2d 517, 519; Katz v. Katz, 412 So.2d 1291, 1293 (La.1982); Smith v. Cajun Insulation, Inc., 392 So.2d 398, 402 n. 2 (La.1980) (“Courts should look through the caption of pleadings in order to ascertain their substance and to do substantial justice to the parties.”).
As in Succession of Smith, we must analyze the pleading at issue and determine what, in reality, it asserts. See 175 So.2d at 271-72. An analysis of Mr. Low-rie’s “Petition for Third Party Claim” discloses that the pleading contends that Mr. Wetzel is a necessary and indispensible party to this suit, that Mr. Wetzel’s income should be included in any child support calculation, and that Mr. Wetzel should be made a party defendant. Therefore, in reality, the pleading presents an LSA-C.C.P. art. 927(A)(4) peremptory exception [579]*579pleading the objection of nonjoinder of a party and a defense on the merits (i.e., owing to the fact that Mr. Wetzel is allegedly the biological father of A.L., a mechanical application of the child support guidelines would be inequitable to Mr. Lowrie, so that a deviation from the guidelines to include the income of Mr. Wetzel is warranted pursuant to LSA-R.S. 9:315.1(B)(1)).
We examine, first, the juvenile court ruling that Mr. Lowrie could not raise a defense as to Mr. Wetzel in this child support action, and, thereafter, we address the nonjoinder issue.4 | ^Parental Duty of Support
What obliges parents to nourish and rear their children is the fact of maternity or paternity. The obligation of support exists even outside of marriage and in favor of illegitimate children. The parent’s duty of support and upbringing is a legal duty owed to the child. Hogan v. Hogan, 549 So.2d 267, 271 (La.1989) (citing 1 M. Planiol, Civil Law Treatise, Pt. 2, §§ 1681-86). The obligation to support their children is conjoint upon the parents, and each must contribute in proportion to his or her resources. Id. See also LSA-C.C. art. 227 (“Fathers and mothers, by the very act of marrying, contract together the obligation of supporting, maintaining, and educating their children.”); LSA-C.C. art. 240 (“Fathers and mothers owe alimony to their illegitimate children, when they are in need .... ”); and LSA-C.C. art. 241 (“Illegitimate children have a right to claim this alimony, not only from their father and mother, but even from their heirs after their death.”).
Filiation is the legal relationship between a child and his parent. LSA-C.C. art. 178. Filiation is established by proof of maternity or paternity or by adoption. LSA-C.C. art. 179.
The husband of the mother is presumed to be the father of a child born during the marriage or within three hundred days from the date of the termination of the marriage. LSA-C.C. art. 185. The presumption that the husband of the mother is the father of the child has been referred to as the strongest presumption in the law. LSA-C.C. art. 185, 2005 Official Revision Comment (b) (citing Tannehill v. Tannehill, 261 La. 933, 261 So.2d 619 (1972); Williams v. Williams, 230 La. 1, 87 So.2d 707 (1956); Katherine Shaw Spaht and William Marshall |sShaw, Jr., The Strongest Presumption Challenged: Speculations on Warren v. Richard and Succession of Mitchell, 37 La.L.Rev. 59 (1976)).
Despite the presumption that the husband of the mother is the father of all children born or conceived during the marriage,5 a biological father in Louisiana is [580]*580entitled to establish his paternity of his illegitimate child, even though to do so may result in “dual paternity” of the child. See T.D. v. M.M.M., 98-0167 (La.3/2/99), 730 So.2d 873, 875-76, abrogated in part on other grounds, Fishbein v. State ex rel. Louisiana State University Health Sciences Center, 04-2482 (La.4/12/05), 898 So.2d 1260.
As stated by this court in T.D. v. M.M.M., certain policy factors favor allowing a biological father to avow his child, even though such action would result in dual paternity, including: a biological father is susceptible to suit for child support until his child reaches majority, and a child who enjoys legitimacy as to his legal father may seek to Mate to his biological father in order to receive wrongful death benefits or inheritance rights. See T.D. v. M.M.M., 730 So.2d at 876. Thus, this court reasoned that it seems only fair, in light of the obligations to which a biological father is susceptible and the multitude of benefits available to the biological child due to the biological link, that the biological father should be afforded at least an opportunity to prove his worthiness to participate in the child’s life. Alternatively, a biological father who cannot meet the best-interest-of-the-child standard retains his obligation of support but cannot claim the privilege of parental rights. See id.
|9The concept of dual paternity in Louisiana was introduced in Warren v. Richard, 296 So.2d 813 (La.1974). See Smith v. Cole, 553 So.2d 847, 850-51 (La.1989). Warren v. Richard addressed the issue of whether an illegitimate child could recover for the wrongful death of a biological father when the child was also the legitimate child of another man under the law, commenting: “It is the dual paternal parentage of this child — one father created by nature, another created by law-which poses the problem we must resolve.” See Warren v. Richard, 296 So.2d at 815.
Warren v. Richard held that “[t]o say that the child ... had no right to recover for her biological father’s wrongful death because the law presumed her to be the legitimate child of another man would run counter to the principles established in the decisions of the United States Supreme Court ... and would ignore the existence of the child’s biological father.” Warren v. Richard, 296 So.2d at 817 (citing Levy v. Louisiana, 391 U.S. 68, 88 S.Ct. 1509, 20 L.Ed.2d 436 (1968)). Such a conclusion, Warren v. Richard noted, was not unique in Louisiana law, pointing to former LSA-C.C. art. 214, which provided that an adopted child is not divested of his right to inherit from his blood parents, upon adoption, while he may also inherit from his adoptive parent.6 Nevertheless, the court indicated that it was “not unmindful of the [581]*581problems a logical extension of these holdings may create, such as a child in these circumstances recovering from both fathers for support and maintenance, or, conversely, requiring the child to support both fathers in a proper case.” See Warren v. Richard, 296 So.2d at 817.
Subsequently, Smith v. Cole considered whether a mother could assert a paternity and support action against an alleged biological father, notwithstanding |inthat the child was conceived or born during the mother’s marriage to another man and was thus the legitimate child of that other man. See Smith v. Cole, 553 So.2d at 848. Applying the concept of dual paternity, Smith v. Cole held that a biological father has an obligation to support his child regardless of the child’s status as the legitimate child of another man, stating: “Since [the legal father’s] failure to disavow paternity would not preclude [the biological father] from bringing an avowal action, it would be unjust to construe the presumption so as to provide [the biological father] with a safe harbor from child support obligations.” Id. at 854.
In reaching its decision, the Smith v. Cole court noted that “the family unit concept,” which was aimed at the preservation of family values, had begun to succumb to the equal protection rights of illegitimate children, obviating the need to protect children against the legal stigmas attached to illegitimacy. See Smith v. Cole, 553 So.2d at 850 n. 4. See also Pociask v. Moseley, 13-0262 (La.6/28/13), 122 So.3d 533, 538; Gallo v. Gallo, 03-0794 (La.12/3/03), 861 So.2d 168, 174; T.D. v. M.M.M., 730 So.2d at 878-79 (Justice Knoll, concurring) (“Where a marital unit is intact, the State’s interest in preserving the integrity of the marital family may also silence a biological father’s competing interests.... However, once the bonds of matrimony are dissolved a vinculo matrimonii, the State’s interest in preserving the marital family disappears.... Today’s realities are that illegitimacy and ‘broken homes’ have neither the rarity nor the stigma as in the past. When parenthood can be objectively determined by scientific evidence, and where illegitimacy is no longer stigmatized, presumptions regarding paternity are ‘out of place.’ ”).
While the legal father presumption promoted the policy against bastardizing children, it often failed to conform with reality by conclusively presuming, as legal father, a husband who could not possibly be, or who clearly was not, the biological Infather (such as when a husband and wife separated for many years before the birth of a child, though they had not divorced, and, at the time of the birth, the mother was living in a stable union with another man, who was the actual biological father of the child). See Smith v. Cole, 553 So.2d at 850 (citing Succession of Mitchell, 323 So.2d 451 (La.1975)). Considerations such as these prompted the legislature to enact codal amendments making the “irrebutta-ble” legal father presumption rebuttable, but the amendments did not alter the rule that only the husband or his heir may disavow paternity.7 See id.
[582]*582Thus, it is well-settled that the legal father presumption should not be extended beyond its useful sphere. Smith v. Cole, 553 So.2d at 854. The presumption was intended to protect innocent children from the stigma attached to illegitimacy and to prevent case-by-case determinations of paternity. It was not intended to shield biological' fathers from their support obligations. The legally-presumed father’s acceptance of paternal responsibilities, either by intent or default, does not enure to the benefit of the biological father. It is the fact of biological paternity or maternity that obliges parents to nourish their children. The biological father does not escape his support obligations merely because others may share with him the responsibility. Biological fathers are civilly obligated for the support of their offspring. They are also criminally responsible for their support.8 Id. “[T]he fact that there is a biological father capable of providing | ^support cannot equitably be ignored,” and “[t]he biological father and the mother share the support obligations of the child.” Id. at 855.
Therefore, in the instant case, there can be no doubt that if Mr. Wetzel is the biological father of A.L., he has an obligation to contribute to her support.9
Left undecided in Smith v. Cole was the question of whether the legal father also would share the support obligation, as the legal father was not a party named in the suit and therefore was not before the court. However, it was noted that the best interest of the child should be considered in determining whether the court in a given case would impose the obligation of support on the person who, by virtue of the legal father presumption, is conclusively presumed to be the father of the child. See id.
As in Smith v. Cole, we are not called upon to determine here whether the legal father must contribute to the support of the child, who he claims is not his biological child; rather, the issue for resolution is whether the legal father, in a state-filed child support enforcement action, is entitled to have the court consider the income of the alleged biological father in calculating the child support obligation and whether the alleged biological father should be joined as a defendant in the action.
Louisiana’s Child Support Enforcement Law
Child support enforcement actions in Louisiana are’ authorized by LSA-R.S. 46:236.1.1 et seq. DCFS is authorized by LSA-R.S. 46:236.1.2 to: (1) enforce, collect, and distribute any established support obligation owed by any person to his child or children; (2) locate absent parents; (3) establish paternity; (4) obtain and modify family and child support orders; and/or (5) obtain and modify medical | ^support orders.10
[583]*583Further, DCFS may also institute civil actions, including actions to establish filiation, “against an alleged biological parent notwithstanding the existence of a legal presumption that another person is the parent of the child” to obtain an order, judgment, or agreement of support against the responsible person in any case in which the department is providing services under the child support enforcement provisions, except when it is not in the best interest of the child. See LSA-R.S. 46:236.1.2(D)(1) (emphasis added). A separate and distinct cause of action in favor of DCFS is created by LSA-R.S. 46:236.1.2(D)(1), and suits brought under this provision “need not be ancillary to or dependent upon any other legal proceeding.” 11
Louisiana courts have imposed child support obligations on biological fathers, in child enforcement suits filed by the State, even when the child has a legally-presumed father, holding that the concept of “dual paternity” and the child support enforcement law, LSA-R.S. 46:236.1.1 et seq., empowers the State to file a suit to establish filiation and child support. See State, Department of Social Services in the Interest of P.B. v. Reed, 10-0410 (La.App. 5 Cir. 10/26/10), 52 So.3d 145, 146, writ denied, 10-2611 (La.2/18/11), 57 So.3d 333; State, Department of Social Services, Office of Family Support, Support Enforcement Services in the Interest of Williams v. Howard, 03-2865 (La.App. 1 Cir. 12/30/04), 898 So.2d 443; State in the Interest of Wilson v. Wilson, 37,674 (La.App. 2 Cir. 9/24/03), 855 So.2d 913, 914-15, writ denied, 03-2970 (La.1/16/04), 864 So.2d 633; State, Department of Social Services, Office of Family Support in the Interest of Munson v. Washington, 32,550 (La.App. 2 Cir. 12/8/99), 747 So.2d 1245, 1247-48; State, Department of Health and Human Resources, Office of Family Security, in the Interest of Robins v. Hinton, 515 So.2d 566, 568-69 (La.App. 1 Cir.1987); State Department of Health & Human Resources in the Interest of Guillory v. Guillory, 407 So.2d 1327, 1329 (La.App. 3 Cir.1981) (“We conclude ... that a natural father is within the ambit of primary responsibility for the support of his children.”); State in the Interest of Poche v. Poche, 368 So.2d 175, 176-77 (La.App. 4 Cir.), writ denied, 370 So.2d 577 (La.1979) (“It sufficed to simply determine that the child was in fact the biological child of the alleged father. The fact that the law considered the child to be the legitimate child of another will not alter the result_”).
We note with particular interest the case of State, Department of Social Services in the Interest of P.B. v. Reed, supra, which was, as in the instant case, also filed by the Jefferson Parish District Attorney. In the Reed case, the district attorney filed a “Petition to Prove Paternity and Obtain Child Support,” in the Juvenile Court for Jefferson Parish, against the child’s alleged biological father, even though the child was born during the mother’s marriage to her husband, the child’s legal father. On appeal by the State, its sole assignment of error was that the juvenile court judge erred in the methodology used to calculate the child support obligation of the biological father in a dual paternity situation. See id. at 147. The appellate court noted that the juvenile court had calculated the child support award by taking into account the incomes of the mother, [584]*584the legal father, and the biological father. See id. at 148. Although the appellate court ruled that the juvenile court judge abused her limited discretion in calculating the child support award, the error stated was that the lower court did not use “verified” income statements, such as paycheck stubs, employer statements, or the most recent tax returns from the mother, legal father, and biological father. Id. There |15was no implication in Reed that it was improper to take into account the incomes of the mother, the legal father, and the biological father, only that when doing so the quality of the evidence of income must be as set forth in LSA-R.S. 9:315.2(A). Id. at 148-49.
Further, procedures applicable in child support enforcement actions to determine paternity and fix child support obligations are compatible with Mr. Lowrie’s assertion that Mr. Wetzel’s income should be included in the calculation of child support. See LSA-R.S. 9:396(B)(1) (providing for a procedure whereby a district attorney representing DCFS in a child support enforcement action may, on ex parte motion accompanied by an affidavit executed by a party alleging specific facts tending to prove paternity, obtain a court order “directing the mother, her husband or former husband, child, and alleged father to appear at a certain date and time to submit to the collection of blood or tissue samples” for paternity testing (emphasis added)); LSA-R.S. 46:236.5 (authorizing a hearing officer to order blood and tissue tests for the determination of paternity in accordance with LSA-R.S.- 9:396 et seq. in a child support enforcement action).
In addition, the child support guidelines, LSA-R.S. 9:315 et seq., apply to cases brought by the State under Title 46 (which includes the child support enforcement law, LSA-R.S. 46:236.1.1 et seq.).12 State, Department of Social Services v. Hebert, 612 So.2d 888, 890 (La.App. 5 Cir.1993).13 Revised Statute 9:315.1(A) states that the child support guidelines are to be used in any proceeding to establish or modify child support filed on or after October 1, 1989, and there 11f;shall be a rebuttable presumption that the amount of child support obtained by use of the guidelines is the proper amount of child support. However, the court may deviate from a “mechanical application” of the child support guidelines “if their application would not be in the best interest of the child or would be inequitable to the parties.” See LSA-R.S. 9:315.1(B)(1). See also LSA-R.S. 9:315.1(0;14 LSA-R.S. 9:315.2(0;15 [585]*585State in the Interest of Wilson v. Wilson, 855 So.2d at 914-16.16
Clearly, existing laws provide the procedures by which an alleged biological father’s paternity could be determined and his contribution to the child’s support could be assessed, within the context of a child enforcement action, and such has been done in prior cases, and such is in accord with express legislative policy.17 117Therefore, we conclude that Mr. Low-rie’s asserted defense, that he be accorded a deviation in the mechanical application of the child support guidelines to take into account Mr. Wetzel’s income, if Mr. Wet-zel’s paternity of A.L. is proven, should not have been summarily dismissed.
We reject the State’s argument that this court should refrain from allowing a legal father, such as Mr. Lowrie, from asserting a defense that requires joinder of an alleged biological father, such as Mr. Wetzel, because of the “potential of causing enormous delays” in establishing [586]*586support orders, both in the first instance and in the case of subsequent modifications of support orders. The State argues that it receives “approximately 6 applications” for support enforcement per year in Jefferson Parish involving both a legal father and a biological father and that allowing a legal father to bring into the case an alleged biological father who has not been filiated to the child “opens the door” for any presumed father sued for child support “to allege that some other man is the biological father of the child and bring him into the suit so that his income may be considered in the child support calculation.” This, the State argues, would “create a mountain of issues and delays in the enforcement of child support as a whole.” While it is commendable that the State is concerned about the potential for litigation - delays in such circumstances, the directive found in Civil Code Articles 240 and 241, that fathers must provide support for their illegitimate children when in need, must prevail over case management concerns. We further note that the filing of wholly | ^unsubstantiated and frivolous claims runs the risk of sanctions pursuant to LSA-C.C.P. art. 863 and, in any event, in this case the mother’s admissions and the biological father’s DNA test results clearly provide a good faith basis for Mr. Lowrie’s pleadings.
Nonjoinder of Biological Father
We next address Mr. Lowrie’s allegations that Mr. Wetzel is a “necessary and indispensable party” and that he should be “named as a defendant in this matter.” These allegations present an LSA-C.C.P. art. 927(A)(4) peremptory exception pleading the objection of nonjoin-der of a party.18
Code of Civil Procedure Article 641 provides that a person shall be joined as a party in the action when either: (1) in his absence complete relief cannot be accorded among those already parties; (2) he claims an interest relating to the subject matter of the action and is so situated that the adjudication of the action in his absence may either: (a) as a practical matter, impair or impede his ability to protect that interest; or (b) leave any of the persons already parties subject to a substantial risk of incurring multiple or inconsistent obligations. See also Industrial Companies, Inc. v. Durbin, 02-0665 (La.1/28/03), 837 So.2d 1207, 1217 n. 6 (“The 1995 amendments to Louisiana’s joinder articles, La.Code of Civ. Proc. Art. 641 et seq. eliminated the categories of ‘indispensable parties’ and ‘necessary parties’ in favor of a single category of ‘parties needed for just adjudication.’ ”).19
[587]*587|iaIf Mr. Lowrie can establish that Mr. Wetzel is the biological father of A.L. at the trial of this matter, then the joinder of Mr. Wetzel (who, if a parent, may be or should be contributing to the support of A.L.20) is needed in this support enforcement action since, in his absence, the determination of the support currently available to A.L. and the support that is needed from Mr. Lowrie cannot be completely determined.
We reject the State’s contention that DCFS “policy” prohibits a child support enforcement action against an alleged biological father when the mother has not named the alleged biological father on her application for support services. Since A.L.’s mother did not name Mr. Wetzel as an alleged father on her application for services, rather, she named only Mr. Low-rie, the State claims it was unable to pursue Mr. Wetzel for child support.
UoRegardless of the internal “policies” of DCFS, the statutory law cited herein prevails over an agency’s internal “policies” or customs. See LSA-C.C. art. 1 (“The sources of law are legislation and custom.”); LSA-C.C. art. 2 (“Legislation is a solemn expression of legislative will.”); LSA-C.C. art. 3 (“Custom results from practice repeated for a long time and generally accepted as having acquired the force of law. Custom may not abrogate legislation.”); LSA-C.C. art. 1, 1987 Revision Comment (a) (“Articles 1 and 3 of the Louisiana Civil Code of 1870 make it clear that the sources of law in Louisiana are legislation and custom. However, as in all codified systems, legislation is the superior source of law in Louisiana.”). The regulations promulgated by an agency may not exceed the authorization delegated by the legislature. An agency exercising delegated authority is not free to pursue any and all ends, but can assert authority only over [588]*588those ends which are connected with the task delegated by the legislative body. The open-ended discretion to choose ends is the essence of legislative power; it is this power that the legislative body possesses, but its agents lack. State v. Alfon0so, 99-1546 (La.11/23/99), 753 So.2d 156, 161-62. See also LSA-R.S. 49:963.21
Pursuant to LSA-R.S. 46:102, DCFS has authority to “make and promulgate all rules and regulations and take such action as may be necessary or desirable for carrying out the provisions of the public welfare laws.” The rules and regulations so promulgated must be complied with “so that the spirit and purposes of the public welfare laws may be achieved.” LSA-R.S. 46:102.
One of the laws DCFS is charged with carrying out, in the area of child support enforcement, is LSA-R.S. 46:236.1.2(D)(1), which authorizes DCFS to |21“take direct civil action, including actions to establish filiation against an alleged biological parent notwithstanding the existence of a legal presumption that another person is the parent of the child solely for the purpose of fulfilling its responsibility under this Section,” except when it is not in the best interest of the child. See also LSA-R.S. 46:236.1.12(A) (“Obligations ordered for support of a child are for the use and benefit of the child and shall follow the child.”) and LSA-R.S. 46:236.1.9(A) (“The agencies, courts, and persons in Louisiana carrying out provisions of this Subpart [Subpart B. Child Support Enforcement] ... shall have the affirmative responsibility to act in the best interest of the individual o.n whose behalf action is taken.”).
The best interest of a child who is in necessitous circumstances, generally, is to recognize the tie to his biological father, as such recognition results in the biological father being obligated to provide his child with support.22 See Smith v. Cole, 553 So.2d at 854.
In addition, the legislature has determined and declared that the enforcement of child support orders and the collection of child support is in the best interest of its citizens by providing resources for the children who are the beneficiaries of those payments and by relieving burdens upon the public fisc. LSA-R.S. 46:238(A). In furtherance its obligation to protect public assistance resources,23 DCFS is required by LSA-R.S. 46:105 and LSA-R.S. 46:106 to investigate “the circumstances” of an applicant for assistance, to “ascertain the facts supporting the application and such other information as may be required by the rules and regulations of the department” to determine an applicant’s eligibility for assistance. Obtaining services from DCFS by false statement, misrepresentation, or other |aafraudulent device is prohibited. See LSA-R.S. 46:114.24
[589]*589In summary, the cited statutory provisions obligate DCFS to act in a child’s best interest, which generally includes acting to establish paternity as to a child’s biological parent, who then can be compelled to provide child support to the child. DCFS also has an obligation to the public to obtain orders of child support to provide resources for children so they are not a burden on the public fisc. DCFS is charged with investigating applications for assistance to deter the obtaining of services by false statements, misrepresentations, and/or fraud.
Therefore, to the extent the DCFS “policy,” upon which the State relies to justify its failure to join the alleged biological father in this child support enforcement suit, sanctions the failure of A.L.’s mother to name A.L.’s biological father, the failure of A.L.’s mother to disclose the extent of financial support provided by A.L.’s biological father, and/or DCFS’s failure act upon the existence of a biological father, such “policy” contravenes statutory law, exceeds DCFS’s authority to promulgate rules, and, thus, such a “policy” is unenforceable.25 See IjKjLSA-C.C. arts. 1-3; LSA-R.S. 49:963; State v. Alfonso, supra.
CONCLUSION
As we stated in Smith v. Cole, the mere fact that a legal father provides child support does not excuse the biological father from his obligation of support. See Smith v. Cole, 553 So.2d at 855. Even though Mr. Lowrie has been required to provide support, as the legal father of A.L., via this child support enforcement proceeding, Mr. Lowrie’s “acceptance of paternal responsibilities ... does not enure to the benefit of the biological father,” alleged to be Mr. Wetzel. See id. at 854. Although the State may not have been aware at the time the instant suit was filed that Mr. Wetzel was believed by the parties to be A.L.’s biological father, once the information was [590]*590disclosed during the course of this litigation, the State had the duty to petition the court to obtain: the maximum possible amount of child support for A.L., thereby also protecting the public fisc as required by LSA-R.S. 46:238(A); the equitable application of LSA-R.S. 9:315 et seq. in the calculation of A.L.’s child support; and the enforcement of the express legislative policy of this state by establishing A.L.’s filiation to her biological father, notwithstanding the existence of a legally-presumed father, unless it was not in A.L.’s best interest, pursuant to LSA-R.S. 46:236.1. If it is proven that Mr. Wetzel is the biological father of A.L. and is, therefore, legally obliged to contribute to A.L.’s support, Mr. Lowrie should be entitled to a deviation in the calculation of the child support obligation to include in the calculation the income of Mr. Wetzel, as authorized by LSA-R.S. 9:315.1(B)(1). Therefore, pursuant to LSA-C.C.P. art. 641 et seq., Mr. Wetzel is a person who should be joined as a party in this action as complete relief cannot be accorded in his absence.
For these reasons, we conclude the juvenile court erred in summarily | ^dismissing Mr. Lowrie’s defense, based on Mr. Wet-zel’s alleged paternity, and the court erred in failing to order the joinder of Mr. Wet-zel.
DECREE
Accordingly, we reverse the Jefferson Parish Juvenile Court’s February 24, 2014 judgment of dismissal, and we remand this matter to the Jefferson Parish Juvenile Court for further proceedings consistent with the foregoing.
REVERSED AND REMANDED.
Judge Scott J. Crichton, assigned as Justice ad hoc, sitting for Justice Jeffrey P. Victory, for oral argument. He now sits as an elected Associate Justice at the time this opinion is rendered.