Autism is a severe disorder of brain function marked by problems with social contact, intelligence, and language, together with ritualistic or compulsive behavior and bizarre responses to the environment. Autism is a lifelong disorder that interferes with the ability to understand what is seen, heard, and touched. This can cause profound problems in personal behavior and in the ability to relate to others.

Autism is a brain disorder that affects the way the brain uses or transmits information. Studies have found abnormalities in several parts of the brain that almost certainly occurred during fetal development. The problem may be centered in the parts of the brain responsible for processing language and information from the senses.

There appears to be a strong genetic basis for autism. Identical twins are more likely to both be affected than non-identical twins. In a family with one autistic child, the chance of having...