This analysis revisits recent controversial findings about children of gay and lesbian parents, and shows that family instability explains most of the negative outcomes that had been attributed to gay and lesbian parents. Family transitions associated with parental loss of custody were more common than breakups of same-sex couples among family transitions experienced by subjects who ever lived with same-sex couples. The analyses also show that most associations between growing up with a single mother and later negative outcomes are mediated by childhood family transitions. I show that many different types of childhood family transitions (including parental breakup and the arrival of a parent’s new partner) are similarly associated with later negative outcomes.