2. Meet Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV) criteria. DSM-IV criteria for Autistic Disorder or Asperger's Disorder (autism spectrum disorder) will be confirmed by a clinician with expertise with individuals with ASD. Best estimate Diagnosis will be reached using DSM-IV criteria, the Autism Diagnostic Observation Schedule (ADOS-G) and the Autism Diagnostic Interview-Revised (ADI-R).