This paper reviews research evidence regarding the personal and social development of children with gay and lesbian parents. Beginning with estimates of the numbers of such children, sociocultural, theoretical, and legal reasons for attention to their development are then outlined. In this context, research studies on sexual identity, personal development, and social relationships among these children are then reviewed. These studies include assessment of possible differences between children with gay or lesbian versus heterosexual parents as well as research on sources of diversity among children of gay and lesbian parents. Research on these topics is relatively new, and many important questions have yet to be addressed. To date, however, there is no evidence that the development of children with lesbian or gay parents is compromised in any significant respect relative to that among children of heterosexual parents in otherwise comparable circumstances. Having begun to respond to heterosexist and homophobic questions posed by psychological theory, judicial opinion, and popular prejudice, child development researchers are now in a position also to explore a broader range of issues raised by the emergence of different kinds of gay and lesbian families.