ABCNews -- For parents of children with autism, the knowledge that some unknown chemical caused their child's developmental disorder can weigh heavily on their minds.
Researchers think that a complex combination of genetic and environmental factors contributes to autism, but they don't know what all those environmental factors are.
A preliminary study out of California might have uncovered at least one chemical worthy of investigation: pyrenthrin, a type of pesticide found in common products, from pet shampoos to household bug killers.
Mothers of more than 500 young children (some autistic, some not) participated in the study, reporting long lists of products they remembered using from a few months before conception until their child turned 1....