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
. At Engskolen, Fensmark School and Frederiksgårs School, which are schools for mentally handicapped and mentally retarded children easier, six out of ten children are bilingual.This phenomenon is allowed for by Islam's marriage law, which is delineated in Qur'an 4:23-34, making this something for which Sharia opens the door.