Trump and RFK Jr. are making claims about autism. What do medical experts say?

Agriculture Secretary Brooke Rollins, President Donald Trump, Health and Human Services Secretary Robert F. Kennedy Jr. and Education Secretary Linda McMahon attend an event for a new Make America Healthy Again Commission report in the East Room of the White House on May 22, 2025 in Washington, D.C. (Photo by Chip Somodevilla/Getty Images)

WASHINGTON — Health and Human Services Secretary Robert F. Kennedy Jr. stirred up major concerns and considerable speculation earlier this year when he announced the administration would release a report revealing the causes of autism by the end of September. 

Kennedy, an environmental lawyer with no medical degree, stood next to President Donald Trump on Sept. 22 as they presented the over-the-counter drug Tylenol as one potential driving factor behind autism diagnoses and pointed to folate, a B vitamin, as a possible treatment — both conclusions the medical community hasn’t yet reached. 

Kennedy throughout his tenure has also made overly broad and disparaging statements about people who have an autism diagnosis, often referring to traits exhibited in people with the most severe cases. For example, he claimed in April that children with autism would never function as independent adults, drawing intense criticism for making a generalization that would not apply to every person with a diagnosis.

The Trump-Kennedy announcement and Kennedy’s characterizations have raised questions about why someone would be diagnosed, what types of research have been done and what reputable science has found about causes. 

States Newsroom spoke with three experts before the announcement to gain a better understanding of autism spectrum disorder. Below are brief excerpts from those interviews. 

What is autism spectrum disorder? 

The two core characteristics of autism are challenges with social communication and the presence of restrictive and repetitive behavior, according to Autism Science Foundation Chief Science Officer Dr. Alycia Halladay. 

As understanding of the diagnosis has evolved, she explained, researchers and families have increasingly referred to it as autisms, plural, instead of autism, singular, in part, because there are so many different subtypes.

“It makes it more accurate when describing it — that autism is not just one entity of core autism features, that there is so much diversity across the spectrum, that it’s actually a group of developmental disorders,” Halladay said. 

The spectrum, she said, ranges from people who may speak rarely to those who are fluent in language, people with cognitive disabilities to those with IQs of more than 120 and people who can live independently to those who need round-the-clock care.

Dr. Michael Murray, a professor in the Department of Psychiatry and Behavioral Health at the Penn State College of Medicine, described it as “a neurodevelopmental disorder, meaning that people are born with it and it’s lifelong and it can cause a variety of challenges for people.”

“The most common and significant and probably pervasive symptom across the spectrum is challenges in understanding and interpreting what we call neurotypical — meaning everyone who is non-autistic — social behavior,” Murray said. “So just understanding all the non-verbal parts of social communication, understanding nuance and non-literal use of language. All those things can be really difficult for autistic people.”

Approximately 1 in 31 children in the United States and 1 in 45 adults fall somewhere along the autism spectrum, according to the advocacy organization Autism Speaks. 

How is autism diagnosed?

Only an expert can diagnose an autism spectrum disorder using criteria in a guide used by health care professionals called the Diagnostic and Statistical Manual of Mental Disorders, or DSM. 

“You need someone who knows autism, who knows what to look for, who knows how to elicit behaviors or not elicit behaviors that are indicative of an autism diagnosis,” Halladay said. “So it’s really diagnosed by a psychiatrist, a psychologist, or somebody else who’s trained to understand what autism is and what it’s not.”

Murray said there are three social communication behaviors that doctors or other qualified medical professionals look for when considering whether to diagnose someone with autism. 

“It is difficulty in interpreting social information. It is difficulty giving social information through things like facial expression and tone of voice. And thirdly, is a difficulty maintaining appropriate peer relationships,” Murray said. “Now, once again, this is from a neurotypical description of peer relationships. There’s a lot of talk among neurodivergent individuals about whether that’s fair, that we rate social relationships based on how we think they should be. But nonetheless, that’s the criteria.”

Murray explained experts also observe the presence of restrictive and repetitive behaviors in assessing whether someone has autism. 

“And that captures things that are in the realm of interacting with the physical world around you,” Murray said. “So that need for sameness and inflexibility maintaining routines.”

Carissa Cascio, a senior scientist at the University of Kansas Life Span Institute and Kansas Center for Autism Research and Training, reinforced that autism is “strictly diagnosed based on behavior.”

“There are genes that have an association with autism that you can test for. There’s some genes that have a very strong association, and you can do a test for the presence of one of those genes,” Cascio said. “But for the diagnosis of autism itself, it’s strictly based on behavior.”

What do we know about the causes of autism?

While more scientific research is needed, a combination of genetics and environmental factors is responsible for the formation of autism spectrum disorders. 

“We know that one of the largest causes of autism is genetics. We know this because it runs in families,” Halladay said, adding there “are over 150 known genes associated with autism.”

“If there’s a variation in the gene, there’s a high likelihood of having an autism diagnosis,” she said. “And those genes are genes that tell cells in the brain where to go and how to connect, which seems to be a core biological feature of autism.”

Halladay emphasized that research has established the “most important part is the interaction between genetics and the environment.”

“Neither the gene nor the environmental factor is strong enough, but together, they increase the probability of having a child with autism,” Halladay explained. 

During the last 25 years, as Murray has advanced in his career, the medical community’s thinking about and understanding of autism spectrum disorders has “significantly increased.”

“We know right now that 80 to 90% of autism is accounted for by genetic differences …. It’s not just you got exposed to this thing in the environment, now you have autism. You have to have the genetic susceptibility first and then the environment might make it more likely, or maybe influence the expression of it,” Murray said.

Cascio said that when it comes to environmental factors, studies have shown pregnancy or the very early post-natal time frame are key. 

“We’re still parsing this out, but some of the environmental factors that seem to have more evidence behind them than others are older parental age, perinatal trauma, premature birth and low birth weight,” Cascio said. “And then there’s some maternal health factors that are gathering some evidence as well. So maternal infection and immune response, maternal exposure to medications or pollutants are sort of gathering some evidence.” 

While much more research is needed on the many potential environmental factors, Cascio said scientists know vaccines are not a component. 

“The things that we definitely can rule out are things that have been studied in great depth and not really produced much association. So you know, the idea that vaccines cause autism is a common belief. There have been dozens and dozens of studies that have all failed to find any association between vaccines and autism,” Cascio said.

There’s also not yet a clear link with Tylenol, also called acetaminophen, as a possible environmental factor. 

“It is unlikely that this is the smoking gun that they’re hoping for,” Cascio said. “I think we all want to understand this better, but this is certainly not something that we feel has a strong weight of evidence behind it yet.”

A spokesperson for Kenvue, the company that manufactures Tylenol, wrote in a statement released in connection with the Trump-Kennedy press conference that “acetaminophen is the safest pain reliever option for pregnant women as needed throughout their entire pregnancy.  

“Without it, women face dangerous choices: suffer through conditions like fever that are potentially harmful to both mom and baby or use riskier alternatives. High fevers and pain are widely recognized as potential risks to a pregnancy if left untreated.”

Why have autism diagnoses increased over several decades? 

Health and Human Services Secretary Kennedy has repeatedly raised concerns with an increase in autism diagnoses over several decades, but experts say there are logical reasons for this. 

“In the early 1990s the CDC set up a system to collect and count the number of people with autism,” Halladay said. “So it definitely has increased since then, but one of the main reasons that’s been shown over and over again is access to services.”

Halladay believes most of the increase is due to greater knowledge and access, though she said, “there is room for some of the increase in autism to be a true increase in the number of people with autism due to something else.”

Murray explained that about 60% to 70% of people diagnosed as being on the autism spectrum are characterized as having “low-support needs, meaning that they clearly have the features of autism, but they are able to, with the appropriate level of supports, be in traditional schools or typical schools; they can, with job support, work and lead their lives the way they choose to.”

When Murray began his career, he said, those people never would have been diagnosed as having autism.  

“Secondly, we as a professional community are getting better and better at picking up these symptoms, particularly in kids who are quite young,” Murray said.

During the late 1980s and 1990s, Cascio said, a new version of the DSM and better tools helped medical professionals more accurately diagnose people along the entire autism spectrum. 

Additionally, Cascio said, there’s a similar concept called diagnostic substitution, where people who in the past may have been diagnosed with something else are now being correctly diagnosed with autism. 

How much research has been done on autism and over how many years?

Scientists have been researching autism for decades, building on past work to better understand how to diagnose and assist people across the spectrum, though experts said more is needed.

“The many, many scientific discoveries and funding into understanding autism has promoted scientists moving into the field,” Halladay said. “So there’s clearly an increased number over the past two decades of the number of people who are focused on studying autism.”

Murray said the first papers published in scientific journals regarding autism were in 1944. 

“So it is 80 years, at a minimum, of work,” Murray said.

Murray reiterated that autism spectrum disorders are not simple to study and said a “really important paper came out earlier this year talking about how there’s four genetically recognizable subtypes of autism. So it’s not a single autism. It is, at the very least, four autisms, and probably more.”

Cascio said addressing any aspect of autism is complicated.

“The behavior is complex. The genetics are complex. The brain is complex,” Cascio said. “And so this makes it a huge challenge for research. And there’s certainly no possibility that we would go from not fully understanding the causes of autism to having a definitive cause in five months.”

What are some of the biggest misconceptions about autism? 

The internet has led to misinformation, and in many cases disinformation, and health diagnoses are no exception.  

Halladay said people often try to simplify autism or believe an actor’s portrayal in a television show or movie is representative of everyone on the spectrum. 

“I think that because of the narrative of autism being oversimplified, that people are not understanding that it’s a more complex disorder,” she said. 

Murray said the autism spectrum may be pictured as a straight line and an expectation arises when someone is diagnosed that they are in just one spot. 

“That’s not really the way it is. There are needs or strengths that show up variably depending on the demands of the situation,” Murray said. “So for instance, someone who has a really exquisite sensitivity to sound, if they are attending a symphony, that may make that experience so much more rich for him or her versus the average person. 

“But if they are at a rock concert, it may be overwhelming. The same trait can be a source of vulnerability or a strength depending on the situation.”

Murray said there’s often a misconception that all people with autism are antisocial or don’t want to make and maintain friendships.  

“And that’s true for some people, right? They aren’t really interested in social interactions. It’s not their thing,” Murray said. “It’s also true for some neurotypical people that they’re really not interested in social interactions. But the vast, vast majority of autistic individuals just want a friend, and they want someone who they can count on and rely on. They want to be loved, just like everyone else in the world … They just need more supports or different situations to have that happen.”

Cascio said that people can form misconceptions after seeing actors portray people along the spectrum.

“I first became interested in autism after watching the movie ‘Rain Man,’” Cascio said. “And I think there’s a lot of people who see a depiction like that and think, ‘Okay, this is what autism looks like.’ And there’s just so much more complexity and variability from person to person and I would say that’s probably the biggest misconception.”

Cascio said it’s also human nature to want one clear answer to why someone develops autism or any other health diagnosis, but that oftentimes the best science shows a more complicated picture. 

“It’s uncomfortable for us to say, ‘This is really complex and we don’t understand it yet,’” she said. “And so when there is something that people hold up and say, ‘Here’s an explanation.’ I think it can be really tempting for people to just want to have it solved. And that’s a very natural reaction.”