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How many people are affected by autism spectrum disorder (ASD)?

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Researchers don't know exactly how many people in the United States have ASD.

The latest estimates suggest that:

  • About one out of every 68 children in the United States currently has autism.1

The CDC is the government agency that studies how many people have autism and other diseases. Visit the CDC website for more information on how many people have ASD: http://www.cdc.gov/ncbddd/autism/data.html

Is ASD more common now than it was in the past?

Until recently, the percentage of people diagnosed with ASD was rising. Researchers attribute the increase primarily to a broader definition of autism, better efforts in diagnosis, and greater awareness about symptoms. But they can't rule out the possibility that there has been a true increase in the number of autism cases.2 CDC researchers continue to monitor this trend.

Who is at risk for ASD?

Research shows that some groups are at higher-than-normal risk for ASD:3,4,5,6

  • Boys. Data show that boys are four to five times more likely than girls to have autism.
  • Siblings of those with ASD. Among families that have one child with autism, there is a 2 % to 8 % chance that another sibling will have autism. This is much higher than in the general population. The chance is even greater if two older children in the family have autism.
  • People with certain other developmental disorders. ASD commonly occurs with other disorders, such as Fragile X syndrome and tuberous sclerosis.
  • Babies born extremely preterm (before 26 weeks into pregnancy).
  • Children of older mothers and fathers.

More research is needed to better understand why these factors increase autism risk.

Race, Ethnicity, and Autism

Current figures show that ASD occurs in all racial, ethnic, and social groups.

Autism is diagnosed more often in some groups than others. However, there is no clear evidence that any racial or ethnic groups are at greater risk for autism than are others.1,7


  1. Christensen, D. L., Baio, J., Braun, K. V., Bilcer, D., Charles, J., Constantino, J. N., … & Yeargin-Allsopp, A. (2016). Prevalence and characteristics of autism spectrum disorder among children aged 8 years—Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2012. Morbidity and Mortality Weekly Report Surveillance Summaries, 65(3), 1–23. Retrieved March 31, 2016, from http://www.cdc.gov/mmwr/volumes/65/ss/ss6503a1.htm [top]
  2. Autism and Developmental Disabilities Monitoring Network Surveillance Year 2010 Principal Investigators, CDC. (2014). Prevalence of autism spectrum disorder among children aged 8 years—Autism and Developmental Disabilities Monitoring Network, 11 Sites, United States, 2010. Morbidity and Mortality Weekly Report Surveillance Summaries, 63(SS02), 1-21. Retreived March 31, 2016 from http://www.cdc.gov/mmwr/preview/mmwrhtml/ss6302a1. [top]
  3. CDC. (2010). Autism Spectrum Disorder (ASD): Data & Statistics. Retrieved March 31, 2016, from
    http://www.cdc.gov/ncbddd/autism/data.html [top]
  4. Muhle, R., Trentacoste, S. V, & Rapin, I. (2004). The genetics of autism. Pediatrics, 113(5), e472-486. [top]
  5. Rutter, M. Genetic influences and autism. In: Volkmar, F. R., Paul, R., Klin, A., Cohen, D., eds. Handbook of Autism and Pervasive Developmental Disorders. 3rd ed. Vol 1. Hoboken, NJ: John Wiley & Sons; 2005:425-452. [top]
  6. Johnson , S., Hollis, C., Kochhar, P., Hennessy, E., Wolke, D., & Marlow, N. (2010). Autism spectrum disorders in extremely preterm children. Journal of Pediatrics, 156(4), 525-531. [top]
  7. CDC (2016). New data on autism: Five important facts to know. Retrieved March 31, 2016 from http://www.cdc.gov/features/new-autism-data/index.html [top]

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