Autism is a neurological disorder thought to be caused by mutant alleles of one or more genes in an individual. scientists had been wondering why the number of children diagnosed as autistic has increased dramatically in the last decade, from 1 in 500 in 2002, to 1 in 88 in 2012. researchers now think that they might have found at least part of the men are fathering children at later and later ages. a paper published in the journal nature in 2012 showed a correlation between paternal age and the incidence of autism; the age of the mother was not a factor. how does this observation provide a possible explanation for the apparent increase in the rate of autism?