It is well known that retarded individuals and those with birth defects
were cast out from villages and cities where they lived on the outskirts,
usually in caves. People of the cities sometimes brought them food or
clothing, and there is no doubt that these indivudals were capable of
drawing. These people would look disfigured and would have had reasonable
cause to breed among themselves. Such disformities are apparent from
inbreeding of royal families, whom later suffer severe genetic disorders.