I have felt for a while that the increase in autism rates is not just better identification, and that it is not all caused by inherited genes. The increase occurred coincident with increased pesticide use and other environmental poisonings. This is not the only environmental cause (air pollution is another), but it is a significant one (25% increase in autism rates in counties that aerial spray pesticides).
http://www.philly.com/philly/health...ide_Spraying_Tied_to_Higher_Autism_Rates.html
http://www.philly.com/philly/health...ide_Spraying_Tied_to_Higher_Autism_Rates.html