socially sanctioned union that reproduces the family . In all societies the choice of partners is generally guided by rules of exogamy (the obligation to marry outside a group); some societies also have rules of endogamy (the obligation to marry within a group). These rules may be prescriptive or, as in the case of the incest taboo, proscriptive; they generally apply to kinship groups such as clan or lineage; residential groups; and social groups such as the ethnic group, caste , or class. Historically marriage was typically heterosexual and entailed exclusive rights and duties of sexual performance, but there are instructive exceptions. For example, Nayar women of India would ritually marry men of a superior caste, have numerous lovers, and bear legitimate children. Among the Dahomey of West Africa, one woman could marry another; the first woman would be the legal “father” of the children (by other men) of the second. These examples highlight the functions of marriage to reproduce…