: sexual intercourse between persons so closely related that they are forbidden by law to marry; also: the statutory crime of engaging in such sexual intercourse
Sexual relations between persons who, because of the nature of their kinship ties, are prohibited by law or custom from intermarrying. The incest taboo is generally universal, although it is imposed differently in different societies. Usually, the closer the genetic relationship between two people, the stronger and more highly charged is the taboo prohibiting or discouraging sexual relations. Some sociobiologists consider that inbred populations have diminished reproductive success and become gene pools for hereditary disorders. Some cultural anthropologists argue instead that the incest prohibition, with the corresponding rules of exogamy, acts to require males to seek sexual and marital partners outside the group, thereby establishing useful alliances. Other theories emphasize the need to control sexual jealousies within the family or to prepare children to function with restraint in adult society. No single explanation seems satisfactory, causing some to question whether incest should be treated as a unitary subject. Most cases of incest that come before criminal courts concern sexual intercourse between fathers and relatively young daughters (seechild abuse).