Cousin marriages has negative impact on intelligence, sanity, health and society. In Pakistan, 70 percent of all marriages are between first cousins (so-called "consanguinity") and in Turkey the amount is between 25-30 percent. Across the Arab world today an average of 45 percent (in some parts up to 70 percent) of married couples are related.
When such people immigrate, they bring their culture with them:
Immigrant children constitute a majority in schools for mentally handicapped and retarded children. The risk of mental and physical disabilities increases significantly when cousins marry each other. Cousin-marriages are highly prevalent in immigrant communities and this is reflected in the number of immigrant children in schools for the mentally retarded. New figures from Copenhagen shows that special schools for children who are born with disabilities or mental retardation, in several cases have a clear majority of immigrant children.