The incest taboo, considered a universal taboo, forbids marriage or sexual relations with a close relative.
However, there are problems with any definition of the incest taboo because the definition of “close relative” varies tremendously among different cultures, the taboo is universal only with very inconsistent applications, some writers restrict the definition to opposite-gender relations, and there are major violations, whatever the definition. Behavior that is strongly, perhaps even fanatically, forbidden in one culture might be accepted, encouraged, or even expected in another culture. Where the taboo is enforced, punishments have ranged from social ostracism to banishment, imprisonment, or death.
There are four inconsistent theories that attempt to explain the taboo’s existence. Claude Lévi-Strauss and others have suggested that the taboo exists to encourage people to marry into other groups (exogamy), in order to build social, economic, or political alliances with other groups and thereby increase the group’s ability to survive and expand. This theory applies particularly to ancient societies when most people lived in small, often isolated and vulnerable groups.
Lewis H. Morgan and others have suggested that sexuality with close genetic relatives can increase genetic diseases or other problems. In actuality, historically, people usually did not understand how genetics affected reproduction. Among modern Western cultures, this explanation is still strongly believed, although modern genetic research does not always support this belief. Genetic problems are more likely to occur in a closed group that inbreeds for several generations than in a onetime, close-cousin reproduction. Moreover, about half of the prohibited incestuous unions in the world have been with genetically unrelated people (e.g., an in-law of some type).
Bronislaw Malinowski and others have said that the incest taboo exists to prevent social role confusion or conflicts within a family, particularly regarding parent-child and sibling roles. Edward Westermarck and others have said that close family members have an instinctual repulsion toward incest, but other theorists suggest that an instinct of such strength would not need a strong cultural taboo. Other researchers point to the frequency of incest despite the cultural taboo or argue that living closely together as in a family leads to the opposite of incestuous desire (referred to as a “habit of avoidance”).
Parent-child and brother-sister incest is the most strongly prohibited, partly because of the assumption of unequal power relationships. In the United States, beginning in the 1970s, largely as a result of encouragement from feminist theorists and conservative voters, this has been a major area of concern, with fervent encouragement of very severe punishments.
There have been several royal families (Egypt, when part of the Roman Empire, the Inca empire, and precolonial Hawaii) that required brother-sister marriages, primarily to maintain the family’s unique sense of divinity. Also, in Egypt, brother-sister marriages were practiced by 15% to 20% of the farming class. First-cousin marriages are legally forbidden in some states in the United States, but practiced in others, and in some Middle Eastern and North African cultures, first-cousin marriages are common. Some preindustrial societies encourage first-cousin marriages for cross-cousins, but not for parallel cousins. Some groups (e.g., Sephardic Jews), have encouraged first-cousin (and uncle-niece) marriages at critical points in their histories. The reasons for the incest taboo have long been, and continue to be, a major debate within anthropology.
- Arens, W. (1986). The Original Sin: Incest and its meaning. New York: Oxford University Press.
- Bell, V. (1993). Interrogating incest: Feminism, Foucault, and the law. New York: Routledge.
- Miletski, H. M. (1999). Mother-son incest: The unthinkable broken taboo. Brandon, VT: Safer Society Press.