Consanguinity

Consanguinity refers to the biological relationship of persons based on their descent from each other or a common ancestor, fachsprachlich consanguinity (Latin consanguinitas: con " together with " and sanguis "blood" ) - in contrast to the legal relationship ( through adoption, paternity or surrogacy ) or in-law by marriage ( affinity). However, an alleged consanguineous parentage does not always correspond to the facts, especially in relation to paternity (see cuckoo children and Lack of proof of paternity ), only modern paternity tests allow biological uniqueness.

Consanguinity plays especially in marriage law a major role, as in most cultures, marriages between blood relatives closest deemed inadmissible ( incest taboo ).

Genetic degrees of relationship

When blood first-degree relatives (parents to children) half of the genes by direct descent are identical. For genetically second degree relatives (grandparents to grandchildren, brothers and sisters to each other ) comes on average a quarter of the genes from a common ancestor. The genetic relatedness is calculated the same as the legal degree of relationship, and similar to the kinship coefficient: It is the shortest Verwandtschaftsweg searched (without loss of ancestors ) between two persons and the number of convictions to determine the total took place there. Alternatively, the sum of the people involved in this pathway are formed (including the starting point and destination). If now this, the reference person ( volunteer) deducted, to the same result follows as in the first method.

Inheritance

In inheritance, the biological relationship has equal status with the legal relationship and forms the basis for the legal order of succession.

Nationality

For citizenship in Germany for a long time was the consanguineous parentage of a person crucial (jus sanguis ); since 2000, he added the " place of birth or territorial principle " (jus soli) is the so-called option model for the application.

Catholic marriage law

In Catholic canon law provides kinship not only in a straight line ( parent- child, grandparent - grandchild ) a marriage obstacle, but also in the collateral line up to the fourth degree ( siblings are blood relatives of the second degree, uncle / niece or aunt / nephew are blood relatives third degree, first cousins ​​are relatives of the fourth degree ). It is among canon lawyers controversial cases in which the impediment to marriage divine right (ie derived directly from the order of creation ) or purely ecclesiastical law. Therefore, more precise can. 1078 § 3 CIC that there are from this obstruction in the straight line (direct Vor-/Nachfahren ) and in the second degree of the collateral line ( siblings) No exemption ( dispensation ).