Autism's a brain development disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior. These signs all begin before a child's three years old. Unusual social development becomes apparent early in childhood. Autistic infants show less attention to social stimuli, smile and look at others less often, and respond less to their own name. Autistic toddlers differ more strikingly from social norms; for example, they've less eye contact and tu… (More on Autism)