 Other arguments for geneticism derive from considering paternity, in that direct genetic derivation appears to provide the most plausible account of the basis of fatherhood. Several recent legal cases have overturned adoptions on the grounds that the estranged father, unidentified at the time of birth, has returned to claim the child (Rosenman 1995, Shanley 1995). Supporters of these decisions endorse the view that unalienated genetic claims to children can override months or even years of rearing by the adoptive parents, as well as the earlier failure of the father to claim the child. Similarly, in “surrogacy” cases, many writers have argued—or simply assumed—that a genetic father may have his own child by contracting with a surrogate mother. This seems to presuppose a genetic account of paternity; and it is a small step from a genetic account of paternity to a genetic account of parenthood. One need appeal only to the principle of “parity,” according to which the sort of relationship that makes one person a parent suffices to make anyone else a parent (Bayne &amp; Kolers 2003; Austin 2004).