consanguinity
noun [ U ] law, biology specialized uk/ˌkɒn.sæŋˈɡwɪn.ə.ti/ us/ˌkɑːn.sæŋˈɡwɪn.ə.t̬i/
血缘关系;血亲;同族
the condition of being blood relations (= related to someone by birth, not marriage)
Some states prohibit marriage where there is a degree of consanguinity. 一些州禁止有某种程度血缘关系的人结婚。