Autism Researchers Seek Cause for Dramatic Rise

For many families, the quest for the causes of autism has grown more urgent with the news that the estimated prevalence of the condition grew by 23% from 2006 to 2008, a Centers for Disease Control and Prevention report said last week.
In most cases, however, scientists can't tell parents what caused their child's autism, says Thomas Insel, director of the National Institutes of Mental Health. In large part, the causes of autism — which is likely not one disease, but a group of conditions with related symptoms — remain a mystery.