Trump Wants to Investigate Why Autism Rates Are Rising. Here's What We Know

During a Dec. 16, 2024, news conference at his Florida residence Mar-a-Lago, U.S. President-elect Donald Trump talked about a rise in autism rates in the United States in recent decades, saying (at the 28:28 mark in the video):

You know, if you look at autism. So, 30 years ago we had, I've heard numbers of like 1 in 200,000, 1 in 100,000 and now I'm hearing numbers of 1 in 100. So something's wrong, there's something wrong. And we're gonna find out about it.

Trump also repeated the claim about autism rates in his speech to Turning Point's AmericaFest event on Dec. 22 (at the 29:41 mark in the video): 

I decided look, something's going on here. When you look at like, autism from 25 years ago. And you look at it now. Something's going on and I nominated Robert F. Kennedy Jr. Think of this. 25 years ago autism: 1 in 10,000 children. Today, it's 1 in 36 children. Is something wrong? I think so. And Robert and I, and all of that, we're going to figure it out.

Trump's claim is supported by research that shows a rise in autism prevalence (now called Autism Spectrum Disorder, or ASD) in recent decades, both in the U.S. and globally. Prevalence in this case means the proportion of people in the population who have an ASD diagnosis at any given time. The Centers for Disease Control and Prevention (CDC) writes that "the prevalence of ASD among 8-year-olds has increased most years since CDC began tracking ASD in 2000." Autism has been part of the Autism Spectrum Disorder (ASD) group of diagnoses in "The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition" (DSM-5) since 2019. The DSM-5 is a taxonomic and diagnostic tool published by the American Psychiatric Association. 

In terms of the other numbers given, Trump's 1 in 36 figure likely stems from CDC figures in 2023 that looked at autism prevalence in 8-year-old children from select states and that were part of the CDC's Autism and Developmental Disabilities Monitoring (ADDM) Network. Separate data from the CDC's "Autism Prevalence Studies Data Table" show that in the U.S. from 1992-1994 — approximately 30 years ago — autism prevalence was measured at 38 in 100,000 children under the age of 18 nationally through parent reports — higher than Trump's Dec. 16 and Dec. 22 estimates. 

Social Factors, Awareness, Capacity Play Key Roles 

Autism researchers point to various reasons to explain the increase in the prevalence of autism in the past few decades. Writing in Autism Research, a journal published by the International Society for Autism Research (INSAR), which promotes research into the disorder, researchers found: "An increase in measured autism prevalence globally, reflecting the combined effects of multiple factors including the increase in community awareness and public health response globally, progress in case identification and definition, and an increase in community capacity."

One example of where increased community awareness could lead to a rise in diagnoses was in California. In March 2010, researchers from Incite, a social science research institute at Columbia University, found that children living nearby other children who received an autism diagnosis were more likely to receive one as well. This was due to interaction between parents and the resulting increase in awareness of the signs of autism in children, according to researchers.

Researchers studying the 2014 National Health Interview Survey in the U.S., a national survey that monitors the health of the U.S. population, also found that in this particular survey, a change in methodology resulted in a rise in reported ASD diagnoses. After surveyors switched the order of questions about ASD and developmental delays to asking about ASD first, ASD diagnoses were found to be higher than expected. Researchers concluded it was likely that, previously, "parents of children diagnosed with ASD reported this developmental disability as other DD [developmental disability] instead of, or in addition to, ASD."

Community capacity, or the ability of a community to detect and diagnose ASD in children, was also credited by researchers as a reason for the increased rise in diagnoses. Examples of this included initiatives such as the CDC's "Learn the Signs. Act Early" program, which helps parents or child care professionals react early if a child is not meeting developmental milestones. The American Academy of Pediatrics now also recommends that children are screened for ASD at 18 and 24 months. Recommendations like these might help initiate ASD assessments that wouldn't have happened before. The CDC's research shows that children are becoming more and more likely to be diagnosed early — 4-year-olds in 2020 (born in 2016) were 1.6 times as likely to have been diagnosed with ASD as 8-year-olds in the same year (born in 2012).

Older Parents Might Cause Rise in ASD Diagnoses

Aside from societal and scientific changes to how professionals diagnose and track ASD, researchers also believe that an advanced parental age for both mothers and fathers plays a role in how likely a child is to be diagnosed with ASD. A study of more than 5 million children from Denmark, Israel, Norway, Sweden and Western Australia found, among other results, that the older the parents were, the higher the "relative risk" of having a child with an ASD diagnosis. 

Birth data from the U.S. showed that the average age of a first-time mother in 2022 was 27.4 years old, up from 27.3 years in 2021 and a "record high for the nation." 

According to the CDC, "studies continue to show that vaccines are not associated with ASD." 

Snopes has previously written about autism, including whether Amish people are diagnosed with the disorder and how misleading research claimed to show links between autism and vaccines.