This chapter examines how the law has responded to the families created through adoption as well as embryo, egg, and sperm donation. It also considers how judicial and legislative interpretations of the implications of reproductive technologies have affected the traditional significance of genetic and marital relationships. The chapter begins by introducing the reader to parentage rights in the United States before turning to a discussion of early cases that struggled with whether children born through gamete provision were “legitimate” or whether the mother had committed adultery. It then reviews relevant laws such as the Uniform Parentage Act, which recognizes the rights of single people to use artificial reproductive technology. Finally, it explores legal issues surrounding parentage and legitimacy, inheritance, incest, artificial insemination, and nonmarital children.