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Autism Spectrum Disorders Health Center

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Who Is Affected by Autism

  • Around the world, about 1 out of 1,000 children has autism.1 And more may show some features of autism. A Centers for Disease Control and Prevention (CDC) study shows that up to 1 out of 110 children in the United States has an autism spectrum disorder (ASD).2
  • It is likely that most cases of autism are passed down through families. Couples who have one child with autism are more likely to have a second child with autism than couples who do not have a child with autism.2
  • Boys are 4 to 5 times more likely than girls to have autism.2

Studies show that autism may be recognized more often than it used to be. This may be because of better detection and a broader definition of autism. For example, some children who were previously diagnosed with intellectual disabilities are now being diagnosed with autism. More study is needed to find the reason for the increase in diagnosis of autism.


  1. Volkmar FR, et al. (2009). Pervasive developmental disorders. In BJ Sadock, VA Sadock, eds., Kaplan and Sadock's Comprehensive Textbook of Psychiatry, 9th ed., vol. 2, pp. 3540-3559. Philadelphia: Lippincott Williams and Williams.

  2. Centers for Disease Control and Prevention (2009). Prevalence of autism spectrum disorders-Autism and developmental disabilities monitoring network, United States, 2006. MMWR, 58(SS-10): 1-20. Also available online:

By Healthwise Staff
Primary Medical Reviewer Susan C. Kim, MD - Pediatrics
Specialist Medical Reviewer Fred Volkmar, MD - Child and Adolescent Psychiatry
Last Revised April 12, 2010

WebMD Medical Reference from Healthwise

Last Updated: April 12, 2010
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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