A risk factor is something that raises your chances of getting a health problem. Autism spectrum disorders (ASD) can happen with or without any of the risks listed below. The more that are present, the higher the chances that ASD can develop. There is no known way to change your child's risk for ASD.

There has been much attention in the media about a link between ASD and vaccines. This is partly because of a vaccine preservative called thimerosal. No studies have found any link between vaccines and ASD.

ASD is more common in white males. But when girls have ASD, their symptoms may be more intense.

Other factors that make the risk higher:


ASD tends to run in families. This is mainly true with twins or other siblings.

There may be a link with problems in a certain chromosome and ASD. But it may only affect a small percentage of children.

Age of Parents

Either parent 35 years or older can make the risk of ASD in a child higher. The risk goes up with a parent's age.

Problems from Pregnancy or Birth

Mothers who had problems during pregnancy or birth may raise the risk of ASD risk in their children. This may include:

Other Health Problems

There is a wide range of health issues linked to ASD. These include:


Autism spectrum disorder. National Institute of Mental Health website. Available at: https://www.nimh.nih.gov/health/topics/autism-spectrum-disorders-asd/index.shtml. Updated March 2018. Accessed August 16, 2019.

Autism spectrum disorders. EBSCO DynaMed website. Available at:http://www.dynamed.com/topics/dmp~AN~T113665/Autism-spectrum-disorders. Updated July 1, 2019. Accessed August 16, 2019.

Johnson CP, Myers SM, American Academy of Pediatrics Council on Children with Disabilities. Identification and evaluation of children with autism spectrum disorders. Pediatrics. 2007;120(5):1183-1215.

What is autism spectrum disorder? Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/ncbddd/autism/facts.html. Updated May 3, 2018. Accessed August 16, 2019.

Last reviewed December 2018 by EBSCO Medical Review Board Adrian Preda, MD  Last Updated: 8/16/2019