An interesting article entitled N.Y. High Court Says Mistaken Avowal of Fatherhood Imposes an ‘Equitable Paternity’ addressed a recent New York appellate decision ratifying the "equitable paternity" doctrine.  This doctrine can come up in the Florida probate litigation context in that the class of persons potentially deemed to be "heirs" of an intestate estate may include a child that was raised by the decedent but never legally adopted.  Here are a few excerpts from the linked-to article:

He who acts like a father, is a father — if not biologically than at least legally — the Court of Appeals said Thursday in imposing "equitable paternity" on a man who wrongly assumed he had fathered a girl and acted accordingly.

The court in Matter of Shondel J. v. Mark D., 40, upheld the trial court and the Appellate Division, 2nd Department, in ordering a man to pay child support on behalf of a child he did not father. In doing so, it recognized the legislatively endorsed concept of "equity paternity," or paternity by estoppel (see Family Court Act §§ 18 [a] and 532 [a]).

The "virtual adoption" doctrine in Florida was articulated in Williams v. Dorrell, 714 So.2d 574, 23 Fla. L. Weekly D1580 (Fla. 3d DCA 1998), as follows:

Virtual adoption is an equitable doctrine created to “protect the interests of a person who was supposed to have been adopted as a child but whose adoptive parents failed to undertake the legal steps necessary to formally accomplish the adoption.” Miller v. Paczier, 591 So.2d 321, 322 (Fla. 3d DCA 1991); see also Sheffield v. Barry, 153 Fla. 144, 14 So.2d 417 (1943). Virtual adoption does not create a parent-child relationship. It is invoked when the adoptive parents die intestate “in order to allow the supposed-to-have-been adopted child to take an intestate share” and to prevent unfair results created by intestacy statutes. Miller, 591 So.2d at 322; see also Tarver v. Evergreen Sod Farms, Inc., 533 So.2d 765, 766 (Fla.1988); Laney v. Roberts, 409 So.2d 201, 203 (Fla. 3d DCA 1982).