Autism

Autism is part of a group of disorders called autism spectrum disorders (ASDs), also known as pervasive developmental disorders. ASDs range in severity, with autism being the most debilitating form while other disorders, such as Asperger syndrome, produce milder symptoms.

• Estimating the prevalence of autism is difficult and controversial due to differences in the ways that cases are identified and defined, differences in study methods, and changes in diagnostic criteria. A recent study by the Centers for Disease Control and Prevention (CDC) reported the prevalence of autism among 8 year-olds to be about 1 in 110.16
• Autism and other ASDs develop in childhood and generally are diagnosed by age three.17
• Autism is about four times more common in boys than girls. Girls with the disorder, however, tend to have more severe symptoms and greater cognitive impairment.16,1

http://www.nytimes.com/2007/08/05/ma...pagewanted=all