Studies of the Genetics of Autism Spectrum Disorders Indicate That

 Studies of the genetics of autism spectrum disorders indicate that ____.

A) many cases result from new mutations or microdeletions in any of a number of genes
B) a small number of genes appear to be involved in autism spectrum disorders
C) most mutations and deletions implicated in autism spectrum disorders are inherited from mothers
D) very young maternal age and very young paternal age independently increase the risk of autism spectrum disorders