How common is autism, really?

Autism spectrum disorder (ASD) is an umbrella term for a range of issues that may affect cognitive, social, emotional, and physical development. It has no single cause, although there are multiple known risk factors, and signs typically surface in early childhood. ASD is a lifelong disorder, though intervention can greatly improve a child’s skills—especially if treatment is started early.

In 2000, about 1 in 150 children in the United States had been diagnosed with autism. By 2020, that number rose to 1 in 36, according to a 2023 report from the Centers for Disease Control and Prevention (CDC).

Are more kids really developing ASD? Or are healthcare providers (HCPs), parents, and schools more aware of signs than they used to be, leading to more diagnoses? Most importantly, what can we do to help children with ASD or a related disorder?

Possible biological and environmental factors

Part of the reason for the rise in diagnoses could be that more children have ASD than in years past. Genetic conditions may be contributing to this. Though additional research is needed, scientists have identified hundreds of genes that can raise risk, and some that can cause the disorder on their own, such as Fragile X syndrome.

Other biological and environmental risk factors could be affecting incidence, as well. For example:

• Older parents—particularly older fathers—are more likely to have children with ASD.
• Having certain health issues during pregnancy, such as gestational diabetes, may raise risk.
• Exposure to air pollution or pesticides can increase ASD risk for vulnerable children, according to some research.

One thing that hasn’t contributed to more widespread ASD: vaccines. The theory stems from a 1998 study that purported to link the measles, mumps, and rubella (MMR) vaccine to autism. Not only has that study been retracted and widely discredited, no link has been proven since.

The impact of greater awareness

While it’s possible that a greater number of children today have ASD compared to previous generations, the bulk of increased diagnoses is due to something different: We're getting better at recognizing the condition. Greater ASD awareness, screening, and access to services are contributing directly to more recorded cases.

This may be especially true among children in historically underserved communities. In the 2023 CDC report, researchers found that ASD is being spotted in Black, Hispanic, and non-Hispanic Asian or Pacific Islander children more often than in previous years. In fact, for the first time since the CDC began reporting, the prevalence of ASD was found to be higher for non-white children than white children.

Girls are being identified with ASD more frequently, too, as experts are better able to discern their early signs, which can differ from those seen in boys. (That said, boys with ASD outnumber girls. About 4 percent of boys are thought to have the disorder, compared to 1 percent of girls.)

Another reason for the surge in reported cases may be changes made to the criteria for autism diagnosis over the years, permitting a wider range of children to be diagnosed. A greater availability of good early interventional services may also make parents more likely to seek care for their children.

The importance of early detection

Children are still being diagnosed for ASD at about 4 years old, on average. But since early intervention is crucial to improving outcomes—and signs of the disorder can surface even before a child turns 1—timely detection and diagnosis are key areas for improvement.

While many children are regularly screened for autism by their HCPs, if you believe your child may be showing signs of autism, it's important to speak up. Your provider can provide screening at any time and refer additional services.

Every U.S. state provides for some early intervention, as well. Reach out to your state's Early Childhood Technical Assistance Center Part C coordinator for additional information on opportunities for screening, diagnosis, and therapies.