Family law, as part of the larger prevailing culture, has enshrined the number two. By constructing links among sex, marriage, and procreation and conceptualizing each as a practice for two, family law takes as its paradigm the couple or the pair. Departures from the twoparty model attract attention—triggering legal sanctions, inspiring scholarly debate, or simply capturing the collective imagination. Recent months have offered one case in point, as courts and a fascinated public followed the raid on the Yearning for Zion compound in Texas and the polygamous residents’ challenge to the familiar spousal dyad. The ongoing conversation about departures from the optimal parental number almost invariably includes criticism of single parents and typically encompasses a wide range of topics, from welfare reform, to marriagepromotion programs, to the legal status of sperm donors who enable women to become single mothers by choice.