Cousins are close relatives and it is illegal to get married. Article 7 of the Marriage Law of the People's Republic of China stipulates that direct blood relatives and collateral blood relatives within three generations are prohibited from getting married. Cousins are collateral blood relatives within three generations, so it is illegal for cousins to get married.

Lineal consanguinity refers to the relatives who are directly related to themselves, that is, the elders who gave birth to themselves include parents, grandparents and grandparents, and the elders and descendants who gave birth to themselves include children, grandchildren, grandchildren and juniors.

Collateral blood relatives refer to blood relatives from the same grandparents, including brothers and sisters (including half-brothers, half-brothers, half-sisters), cousins, uncles and aunts, nephews and aunts. It can be seen that cousins belong to collateral blood relatives within three generations and cannot get married.

Extended data

Inbreeding is because they have too many similar genetic factors, and the offspring can't mutate from them, and the harmful genes are passed on to the offspring.

If this gene is autosomal recessive, its children may get sick because they are homozygotes of the mutation. So inbreeding will increase the risk of some autosomal recessive genetic diseases. Inbreeding increases the probability that children will get such a pair of homozygous or identical genes.

Baidu Encyclopedia-China People's Marriage Law