Where c. 209C is not available as a vehicle for establishing parentage, the Probate and Family Court may do so pursuant to its general equity jurisdiction. See C.C. v. A.B., 406 Mass. 679, 689-690, 550 N.E.2d 365 (1990). See also G. L. c. 215, § 6 (granting general equity jurisdiction to Probate and Family Court).

Probate Court, Paternity proceeding. In a proceeding in the Probate and Family Court, in which the plaintiff sought an adjudication that he was the biological father of two children, the judge's ruling, following a preliminary hearing pursuant to the mandate of C.C. v. A.B., 406 Mass. 679, 689-691 (1990), that the putative father had standing to litigate the issues of paternity, custody, and visitation, was an interlocutory decision, not immediately appealable. [372-375]

The plaintiff now appeals from a judgment of the Probate and Family Court dismissing his paternity complaint on the ground that he failed to demonstrate, preliminarily, the required "substantial parent-child relationship" between himself and the child. See C.C. v. A.B., 406 Mass. 679, 687 n. 8, 689-691 (1990). We affirm.

UPA § 13, 9B U.L.A. 320 (1987); Minn.Stat. § 257.64 (1990). In the third case, C.C. v. A.B., 406 Mass. 679, 550 N.E.2d 365 (1990), the court's decision that a putative father had a common law right to bring a paternity action where the mother of the child was married to another man was based not on "best interests of the child," but rather on the existence of a "substantial parent-child relationship" between the putative father and child. C.C., 406 Mass. at 689-90, 550 N.E.2d at 372.

Moreover, to bring a claim in equity to establish paternity requires establishing a “substantial parent-child relationship” between the putative father and the child. See C.C. v. A.B., 406 Mass. 679, 690, 550 N.E.2d 365 (1990). In the context of assisted reproductive technology, a putative father also may be a biological family member of one of the spouses; the petitioners indicate in their brief that choosing such a donor may allow a nonbiological parent to have a biological tie to the child.

While the common law has always recognized that a child born to a married woman may not have been fathered by her husband, it created a strong presumption of legitimacy to avoid the disadvantages to the child associated with illegitimacy and to safeguard the traditional family. See C.C. v. A.B., 406 Mass. 679, 684, 686, 690–691, 550 N.E.2d 365 (1990). See also R.R.K. v. S.G.P., 400 Mass. 12, 15, 507 N.E.2d 736 (1987).

(Citations omitted). Accord, e.g., Weidenbacher v. Duclos, 234 Conn. 51, 661 A.2d 988 (1995); C.C. v. A.B., 406 Mass. 679, 550 N.E.2d 365 (1990). Thus, with the possible exceptions noted below, a petition by a putative biological father seeking to establish his paternity over a child who was born while the mother was married to another man may not proceed unless the putative father clearly and convincingly proves as a threshold matter that he has established a substantial paternal relationship with the child.

In assessing a child's relationship with his de facto parent, a judge may consider the factors we have set forth previously. For example, in C.C. v. A.B., 406 Mass. 679 (1990), we held that a man could maintain a paternity action under G.L.c. 215, § 6, even though the mother of the child was, at the time of conception and birth, married to another man. Id. at 680. We reasoned that the man demonstrated a substantial parent-child relationship.

In the case of Matter of Marriage of Ross, 245 Kan. 591, 783 P.2d 331 (1989), the Kansas Supreme Court was faced with two competing presumed fathers; and once again blood tests and a relationship were already in existence. In the case of C.C. v. A.B., 406 Mass. 679, 550 N.E.2d 365 (1990), the court held that "[t]he existence of a substantial parent-child relationship is . . . the controlling factor in determining whether [the putative father] may pursue his claim." Id.

Assuming that he may invoke the chapter at this late date, G.L.c. 209C has no application to these proceedings. The purpose of that chapter is "to deal with actions to establish paternity in the context of children born out of wedlock," C.C. v. A.B., 406 Mass. 679, 681 (1990), and to ensure that children born out of wedlock are given the same rights and protections of the law as all other children. G.L.c. 209C, § 1.