Our conclusion that a father may be required to pay child support retroactive to the birth of the child under the UPA is consistent with the result reached by courts in other jurisdictions. Interpreting the Wyoming equivalent of 19-4-116(3)(a), the Wyoming Supreme Court held in Ellison v. Walter ex rel. Walter, 834 P.2d 680 (Wyo. 1992) that a trial court possesses the authority to issue support orders retroactive to the date of a child's birth in paternity/support actions initiated by a state social services agency for the reimbursement of public assistance. The Ellison court also determined that retroactive child support orders should be the rule, rather than the exception.

The appellate division found that the bar of laches would be applicable to deny plaintiff's claim; but it reversed the trial court's decision since "there is no basis to impute to a child the custodial parent's negligence, purposeful delay or obstinacy so as to vitiate the child's independent right of support from a natural parent." Id. at 39-40, 788 A.2d 881 (citing Perez v. Singh, 21 Cal.App.3d 870, 97 Cal.Rptr. 920 (1971); Ellison v. Walter ex rel. Walter, 834 P.2d 680 (Wyo. 1992)). Here, the record shows that plaintiff attempted on numerous occasions to collect un-reimbursed medical expenses from defendant.

Consequently, retroactive child support orders should be the rule, rather than the exception.In re Paternity of JWH , 2011 WY 66, ¶ 28, 252 P.3d 942, 950 (Wyo. 2011) (citing Ellison v. Walter , 834 P.2d 680, 683-85 (Wyo. 1992) ); see alsoThomas v. Thomas , 983 P.2d 717, 721 (Wyo. 1999). Though we start with the presumption that retroactive support is the rule, we have upheld the decision to deny retroactive application of support obligations where the district court makes a specific and rational finding.

The purpose of legislation creating a paternity action is to convert a moral obligation into a legal right." Ellison v. Walter ex rel. Walter, 834 P.2d 680, 683 (Wyo. 1992) (quoting Vigil v. Tafoya, 600 P.2d 721, 725 (Wyo. 1979)). "The establishment of paternity by judicial decree is merely a procedural prerequisite to enforcement of the duty of support owed to the child: it does not create, but only defines the preexisting duty."

Mother argues that Father should be ordered to pay child support retroactive to the child's birth, except for the eight months the parties lived together. [¶ 28] In Ellison v. Walter, 834 P.2d 680, 684-85 (Wyo. 1992), we stated: [T]he duty of a natural father to support his child begins at [his child's] birth.

In a case with somewhat similar facts we held that it was not an abuse of discretion for a district court to award $50.00 a month in back child support retroactive to the date of the child's birth. Ellison v. Walter ex rel. Walter, 834 P.2d 680, 683-85 (Wyo. 1992). [¶ 21] This subject is exhaustively annotated at: Jeffery W. Santema, Liability of Father for Retroactive Child Support on Judicial Determination of Paternity, 87 A.L.R.5th 361 (2001).

The duty of a natural father to support his child begins when the child is born. Ellison v. Walter ex. rel. Walter, 834 P.2d 680, 683-84 (Wyo. 1992).

The analysis we have used in paternity determination/support cases, while not directly on point, is instructive. In Ellison v. Walter, ex rel. Walter, 834 P.2d 680, 684-85 (Wyo. 1992), we stated that a district court possesses the authority to issue support orders retroactive to the date of a child's birth in paternity/support actions initiated by a state for the reimbursement of public assistance.

Dist. Ct. App. 1983); People ex rel. Reeder v. Reeder, 131 Ill. App.3d 841, 86 Ill.Dec. 874, 476 N.E.2d 50 (1985); Howell v. Brummell, 293 Md. 646, 446 A.2d 1149 (1982); M.A.D. v. P.R., 277 N.W.2d 27 (Minn. 1979); McNulty v. Heitman, 600 S.W.2d 168 (Mo. Ct. App. 1980)(superseded by statute on attorney fee question); State ex rel. Dep't of Human Serv. v. Davis, 99 N.M. 138, 654 P.2d 1038 (1982); Williams County Soc. Serv. Bd. v. Falcon, 367 N.W.2d 170 (N.D. 1985); Roboski v. Fink, 447 Pa. Super. 520, 669 A.2d 1017, 1017 (1996); Shell v. Law, 935 S.W.2d 402 (Tenn. App. 1996); Prejean v. Prejean, 592 S.W.2d 660 (Tex. Civ. App. 1979); Nettles v. Beckley, 32 Wn. App. 606, 648 P.2d 508 (1982); Ellison v. Walter, 834 P.2d 680 (Wyo. 1992). [¶ 36.] The general rule, absent statutory preemption, recognizes a presumption of retroactivity of child support to the child's date of birth.

A review of courts interpreting this language shows Uniform Parentage Act § 15(d) has been read as authority to allow a court to award past support. See In Interest of L.W., 756 P.2d 392, 393-94 (Colo.Ct.App. 1988); Rieck v. Lambert, 396 N.W.2d 269, 271 (Minn.Ct.App. 1986); Lamdin v. Ferraro, 270 Mont. 484, 893 P.2d 332, 336 (1995); Nettles v. Beckley, 32 Wn. App. 606, 648 P.2d 508, 510-11 (1982); Ellison v. Walter, 834 P.2d 680, 684-85 (Wyo. 1992). We find the conclusion reached by these courts persuasive and agree with Rydberg past support may be awarded in an action under N.D.C.C. ch. 14-17.