On Feb. 5, 2025, shortly after the U.S. Senate finance committee approved Robert F. Kennedy Jr.'s nomination to become the nation's top health official, President Donald Trump praised Kennedy as being a solution to rising autism rates in the country.
Trump posted on Truth Social, his social media platform (archived):
20 years ago, Autism in children was 1 in 10,000. NOW IT'S 1 in 34. WOW! Something's really wrong. We need BOBBY!!! Thank You! DJT
(@realDonaldTrump on Truth Social)
Kennedy has long promoted the debunked notion that vaccines cause autism. Following the Senate committee's approval of his nomination to lead the Department of Health and Human Services, the full chamber was expected to vote, although this vote had not yet taken place at the time of this writing.
Trump's Truth Social post followed a series of public appearances in which the president made similar claims about autism rates. For instance, during a Dec. 16, 2024, news conference at his Florida residence, Mar-a-Lago, he said (at the 28:38 mark in the video below):
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 claimed in a speech on Dec. 22, 2024, at Turning Point's AmericaFest event (at the 29:41 mark in the below 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 that autism diagnoses have increased 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.
However, the past figures Trump cited were lower than what research suggests.
On a page titled "Frequently Asked Questions about Autism Spectrum Disorder," the Centers for Disease Control and Prevention wrote 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 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 34" or "1 in 36" figures likely stem from CDC figures in 2023 that looked at autism prevalence in 8-year-old children from select states who were part of the CDC's Autism and Developmental Disabilities Monitoring Network.
Separate data from the CDC's "Autism Prevalence Studies Data Table" shows that in the U.S. from 1992 to 1994 — approximately 30 years ago — autism prevalence, measured through parent reports, was 38 in 100,000 children under the age of 18 nationally — higher than Trump's December 2024 estimates. In other words, the research shows that autism rates have increased since the early 1990s, but not as much as Trump claimed.
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.
In a 2022 paper published in Autism Research, a journal published by the International Society for Autism Research, 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."
In an example of how increased community awareness could lead to a rise in diagnoses, researchers from Incite, a social science research institute at Columbia University, found in 2010 that children living near other children who received an autism diagnosis were more likely to receive one of their own.
According to the study's authors, this was due to interaction between parents and the resulting increase in awareness of the signs of autism in children.
Another factor that may have resulted in higher reports of ASD diagnoses was the design of surveys used to measure how many people had been diagnosed with the disorder. Researchers studying the 2014 National Health Interview Survey, a national survey that monitors the health of the U.S. population, 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 be 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 — in 2020, for example, researchers found that children who were 4 that year (that is, children born in 2016) were 1.6 times as likely to have been diagnosed with ASD as children who were 8 (those 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 may play 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, up from 27.3 years in 2021. According to a report on the data published by the National Center for Health Statistics, which is part of the CDC, that data represented a "record high for the nation" in terms of maternal age at first childbirth.
According to the CDC, "studies continue to show that vaccines are not associated with ASD." On an informational page about the disorder, the CDC also noted that scientists do not believe there is a single cause of ASD, which instead appears to be the result of multiple different factors.
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.