Incest

Incest generally refers to sexual relations between close family members, such as brother and sister or parent and child. It is a criminal offence and an impediment to marriage in most modern countries, as well as being against most modern religions. The definitions of "close family member" and "sex" vary widely.

In the United States and other industrialized countries, incest is generally used to refer to forbidden sexual relations within the family. Incest is most frequently a form of child sexual abuse committed by parents of both sexes. And while it is usually perceived as an act done by a father against his daughter, this is yet another myth surrounding the practice. Historically, the most important forms of incest were maternal incest. And while surveys do not indicate a high rate of maternal incest, this is a reflection of the difficulty of collecting information about sexual abuse inflicted on infants.

It is widely, but by no means universally, agreed that incest by parents should be illegal. Some societies, notably India in the 1920s, consider incest an inescapable fact of life. In many societies some forms of sexual contact between close family members is socially (and sometimes even publically) encouraged. For example, in Bali it was encouraged for mothers to sexually stimulate infants. This practice, among many others, is also common among primitive tribes in Papua New Guinea, Polynesian and Melanesian islands. It is also common among the Japanese who claim to have no Oedipal complex "because the father is no competition" to the son.

Examples of incestuous marriages are well-documented among royal families. The Egyptians are only the best known example.

Examples of incest in mythology are rampant. Zeus and Hera are brother and sister as well as husband and wife. They were the children of Cronus and Rhea who were also brother and sister as well as husband and wife.

Finally, there is also the much rarer phenomenon of consensual incestuous relations between adults, such as between an adult brother and sister. This is illegal in most places, but these laws are sometimes questioned on the grounds that such relations do not harm other people (provided the couple have no children) and so should not be criminalised. Artificial insemination and distant adoption have compounded these problems. There are known cases of people having romances, or even marrying, only to later find out they are closely related.

Adult incest has been notable in royal dynasties, presumably to keep the bloodline "pure". Although the marriage unions were often not consensual, with young adults or children forced to marry close relatives, this does not imply the sex was non-consensual. Best known for this practice, which included brother-sister marriages, are the dynasties of Ancient Egypt.