This Article unpacks the relationship between the functional parenthood doctrine, constitutionally protected parental autonomy rights and intent-to-parent tests as they are applied in same-sex parenting relationships. It argues that, with the advent of same-sex marriage and second parent adoption, the functional parent doctrine is unnecessary and ultimately counterproductive to anyone interested in expanding legal recognition of non-traditional family forms. The functional parent doctrine asks courts to employ traditional understandings of parenthood (“Who acted like a parent?”) in assigning parental status.

These traditional understandings are usually, if not inevitably, dyadic, heteronormative, genetic, and gendered. In practice, the functional parent doctrine undermines the legitimacy of single-parent families and any family that does not conform to conventional parenting patterns; it indirectly reinforces the notion that the only parents entitled to robust constitutionally protected parental autonomy are married, genetic, heterosexual parents. Advocates and all those concerned with protecting the integrity of same-sex parenting families would be better served by an intent-based system that asks the parties themselves, not judges, to legally declare their family relationship. At virtually no additional administrative cost, states can offer a parental registration system for same-sex parents that puts the responsibility for defining legal families in the hands of the families, thereby allowing those families considerably more freedom than does the functional parent doctrine, to structure their relationships as they choose.