Implication of sex differences in the familial transmission of infantile autism.

There are studies suggesting possible hereditary influence in autism. Data on 102 autistic children, 78 boys and 24 girls, showed that there was a significantly greater proportion of autistic girls than boys with IQs less than 50 and with evidence of brain damage. The autistic girls also had a greater proportion of relatives affected with autism or cognitive-language deficit than did the boys. The implication of sex differences in the possible mode of familial transmission of autism is discussed.