I do not know about you, but that statistic from the Department of Education about autism really surprised me. I was also surprised that the number of students with autism keeps getting higher, in spite of the fact that the mercury-based vaccine preservative, thimerosal hasn't been used since 2001. I, like many other people, thought that it might be the preservative used in childhood vaccines (and some flu shots) that was causing autism, but according to the study published in the Journal Archives of General Psychiatry, that might not be the case.
Of course, since they do not know what does cause autism, no one can say for sure. One study in California does not "prove" anything, but it does suggest we need to keep doing research on possible cause of autism. Autism is characterized by impaired social interaction and communicating skills, as well as different responses to sights and sounds. It can be minor or severe, usually begins before the age of three and is more likely to occur in boys. There is no cure, but early therapy can lessen the severity. The advocacy group, Autism Speaks and the Centers for Disease Control and Prevention both provide lots of great information and resources about autism.