According to recent estimates from the Center for Disease Control’s Autism and Developmental Disabilities Monitoring Network, autism affects about 1 in 68 children. It is almost 5 times more common among boys (1 in 42) than among girls (1 in 189). Autism occurs in all racial, ethnic, and socioeconomic groups and is the fastest growing developmental disability in the United States. Prematurity, low birth weight, and advanced parental age also increase the risk of developing autism. Parents who have one child with autism have a 2% to 18% chance of having a second child affected by autism.