Incest

Incest, sexual intercourse between closely related individuals, has been a taboo in most societies, primitive and modern. The concept of what constitutes close relatives, however, is not uniform among societies. At one extreme lie the Trobriand Islanders, who prohibit only a relationship between mother and son, allowing all others—including between father and daughter. At the other extreme are perhaps the Chinese, who prohibit marriages between people sharing the same surname, since they are considered related. Variations also occur in regions within the same country. While as many as 50 percent of marriages in southern India are between first cousins, the same is considered abnormal in northern India. Finally, levirate marriages, between a widow and her husband's brother, are not considered incestuous in most societies and ...