Incest law

Laws regarding incest (i.e. sexual activity between family members or close relatives) vary considerably between jurisdictions, and depend on the type of sexual activity and the nature of the family relationship of the parties involved, as well as the age and sex of the parties. Besides legal prohibitions, at least some forms of incest are also socially taboo or frowned upon in most cultures around the world.

Incest laws may involve restrictions on marriage rights, which also vary between jurisdictions. When incest involves an adult and a child, it is usually considered to be a form of child sexual abuse.

Laws regarding incest are sometimes expressed in terms of degrees of relationship. The consanguinity (but not affinity) relationships may be summarized as follows:

The degree of relationships is calculated by counting the number of generations back to a common ancestor. Most laws regarding prohibited degree of kinship concern relations of r = 25% or higher, while most permit unions of individuals with r = 12.5% or lower. In some US states, cousin marriages are prohibited. Also, most laws make no provision for the rare case of marriage between double first cousins. Incest laws may also include prohibitions of unions between biologically unrelated individuals if there is a close legal relationship, such as adoption.

Consensual incest between adults is legal in Côte d'Ivoire (Ivory Coast).

In South Africa, since 2007, incest is the sexual penetration between persons who are related as follows:

Before 2007, incest was a common law offence which extended to the same degrees of relationship but which applied only to vaginal intercourse.

In Zimbabwe, all forms of incest could result in a jail sentence, including cousins as far as fourth cousins.

Barring the Special Administrative Regions of Hong Kong and Macau, which have separate legal codes, consensual incest between adults is legal in the People's Republic of China.

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