consanguinity

consanguinity (kŏn'săng-gwĭn`ĭtē), state of being related by blood or descended from a common ancestor. This article focuses on legal usage of the term as it relates to the laws of marriage, descent, and inheritance; for its broader anthropological implications, see incest. Consanguinity is to be distinguished from affinity, which is the relation of a person, through marriage, to the consanguineous relatives of a spouse. Marriage between persons in lineal consanguinity (persons in the direct line of descent, such as father and daughter) and between brothers and sisters is void under common law, church law, and statute. Whether or not marriages between persons of collateral consanguinity (those having a common ancestor but not related in direct line of descent) are prohibited as incestuous depends on statutory provision and judicial interpretation. In more than half the states of the United States, marriage between first cousins is prohibited by law, and the Roman Catholic Church and the Orthodox Eastern Church have strict rules on consanguinity as an impediment to marriage. Statutes in the United States discard affinal relationship as an impediment to marriage. Whether incestuous marriages are void or voidable in the United States depends on local statutes and their interpretation. In the law of descent and inheritance, the concept of consanguinity is most important in the area of intestate succession. Most states award the spouse of a person who dies intestate a certain share of the estate, even though there exists neither lineal nor collateral consanguinity between the spouses.

Bibliography

See B. D. Inglis, Family Law (2d ed., 2 vol., 1968–70).

---

consanguinity

Kinship characterized by the sharing of common ancestors (derived from the Latin consanguineous, meaning “of common blood”). Kin are of two basic kinds: consanguineous (sharing common ancestors) and affinal (related by marriage). Today consanguinity is a genetic concept that influences the probabilities of specific combinations of characteristics, called genotypes. The probability that two consanguineous individuals will share the same traits depends upon the mode of inheritance (dominant or recessive) and the degree of penetrance or expressivity of the causative gene. Higher rates of mortality and rare diseases and disorders are more common in the offspring of consanguineous unions. While consanguineous marriages of various degrees have been practiced, all societies have incest taboos prohibiting marriage or sexual relations between certain kin.