Consanguinity

Blood relationship; the relation of people who descend from the same ancestor.

Consanguinity is the basis of the laws that govern such matters as rules of DESCENT AND DISTRIBUTION of property, the degree of relation between which marriage is prohibited under the laws concerning INCEST, and a basis for the determination of who may serve as a witness.

Lineal consanguinity is the relation in a direct line—such as between parent, child, and grandparent. It may be determined either upward—as in the case of son, father, grandfather—or downward—as in son, grandson, great-grandson.

Collateral consanguinity is a more remote relationship describing people who are related by a common ancestor but do not descend from each other—such as cousins who have the same grandparents.

Consanguinity is not the same as affinity, which is a close relation based on marriage rather than on common ancestry.