President Donald Trump made controversial claims about autism on Monday during a White House press briefing, announcing that the Food and Drug Administration will warn doctors against prescribing acetaminophen (Tylenol) to pregnant women.
Trump announced that the Food and Drug Administration would begin “strongly recommending that women limit Tylenol use during pregnancy unless medically necessary,” claiming a connection between acetaminophen and increased autism risk. Speaking directly to pregnant women, Trump stated, “Don’t take Tylenol. There’s no downside. Don’t take it,” and advised against giving the medication to newborns.
The president claimed that the FDA would immediately notify physicians about what he characterized as a “very increased risk of autism” associated with acetaminophen use during pregnancy.
“So taking Tylenol is not good,” Trump said. All right. I’ll say it. It’s not good. For this reason, they are strongly recommending that women limit Tylenol use during pregnancy unless medically necessary. That’s, for instance, in cases of extremely high fever, that you feel you can’t tough it out. You can’t do it. I guess there’s that.”
The administration framed these announcements as part of what Kennedy called a bold initiative to confront the nation’s “autism epidemic.” Kennedy, who has long promoted theories linking autism to environmental factors, claimed that autism rates have increased from 1 in 150 children in 2000 to 1 in 31 children currently.
The reality is, though, that credible scientific studies have shown there is no link between acetaminophen or vaccines and autism.
The American College of Obstetricians and Gynecologists (ACOG) released a statement calling the announcement “highly concerning” and “irresponsible.”
“Suggestions that acetaminophen use in pregnancy causes autism are not only highly concerning to clinicians but also irresponsible when considering the harmful and confusing message they send to pregnant patients, including those who may need to rely on this beneficial medicine during pregnancy.
“Today’s announcement by HHS is not backed by the full body of scientific evidence and dangerously simplifies the many and complex causes of neurologic challenges in children. It is highly unsettling that our federal health agencies are willing to make an announcement that will affect the health and well-being of millions of people without the backing of reliable data.
“In more than two decades of research on the use of acetaminophen in pregnancy, not a single reputable study has successfully concluded that the use of acetaminophen in any trimester of pregnancy causes neurodevelopmental disorders in children. In fact, the two highest-quality studies on this subject—one of which was published in JAMA last year—found no significant associations between use of acetaminophen during pregnancy and children’s risk of autism, ADHD, or intellectual disability.
“The studies that are frequently pointed to as evidence of a causal relationship, including the latest systematic review released in August, include the same methodological limitations—for example, lack of a control for confounding factors or use of unreliable self-reported data—that are prevalent in the majority of studies on this topic.
“Acetaminophen is one of the few options available to pregnant patients to treat pain and fever, which can be harmful to pregnant people when left untreated. Maternal fever, headaches as an early sign of preeclampsia, and pain are all managed with the therapeutic use of acetaminophen, making acetaminophen essential to the people who need it. The conditions people use acetaminophen to treat during pregnancy are far more dangerous than any theoretical risks and can create severe morbidity and mortality for the pregnant person and the fetus.
“When considering the use of medication in pregnancy, it’s important to consider all potential risks along with any benefits. The data from numerous studies have shown that acetaminophen plays an important—and safe—role in the well-being of pregnant women.”
While some observational studies have suggested associations between frequent acetaminophen use during pregnancy and neurodevelopmental conditions, researchers stress these do not establish causation.
The 2024 JAMA study involving 2.5 million Swedish children found no causal relationship between prenatal acetaminophen exposure and autism, ADHD, or intellectual disabilities when comparing siblings. The Swedish registry analysis (JAMA 2024) compared over 2.48 million births. Initial models showed a very slight increase in autism in exposed children, but when siblings were compared, this increased risk disappeared, indicating that shared genetic or environmental factors likely explain the association rather than acetaminophen use itself.
“At the heart of this is people trying to look for simple answers to complex problems,” said James Cusack, chief executive of Autistica, a UK autism research charity. Experts consistently emphasize that autism has multiple contributing factors, with genetics playing a major role, and that no single environmental cause has been definitively established.
Alongside the Tylenol announcement, the administration promoted leucovorin (folinic acid), a cancer medication, as a potential autism treatment. The FDA announced it would approve leucovorin tablets for patients with cerebral folate deficiency (CFD), a neurological condition that can present with autism-like symptoms.
The approval is based on a review of studies involving approximately 40 patients with CFD, a rare condition affecting folate transport to the brain. While some research suggests leucovorin may help improve communication skills in certain autistic children, experts stress this applies only to a small subset of patients with specific metabolic conditions.
“A much higher standard of science would be needed to determine if leucovorin is an effective and safe treatment for autism. This science is still in very early stages, and more studies are necessary before a definitive conclusion can be reached. We welcome additional investigation into leucovorin, but based on existing data, the Autism Science Foundation does not recommend leucovorin as a treatment for autism,” the Autism Science Foundation wrote.
The administration’s characterization of autism as an “epidemic” has been disputed by leading autism researchers and organizations. The Centers for Disease Control and Prevention attributes the increase in autism diagnoses primarily to improved recognition, better screening, expanded diagnostic criteria, and increased awareness rather than an actual rise in occurrence.
The Autism Society of America noted that the prevalence increase may reflect several factors including greater awareness, improved screening and diagnostics – especially in communities that were previously underrepresented. The broadened definition of autism adopted in 2013 and concerted efforts to screen more children, particularly in underserved communities, have contributed significantly to higher reported rates.
Autism was not officially recognized as a distinct clinical disorder until 1980, when it first appeared in the DSM-III under the label “infantile autism.” Prior to this, many cases that would now be understood as autism spectrum disorder (ASD) were misclassified under other diagnoses, most commonly childhood schizophrenia. This shift in classification altered how researchers and clinicians viewed developmental differences. For example, when data from a 1980s Utah study was re-analyzed using modern DSM-IV-TR criteria, 64 of 108 children originally considered “Not Autistic” met criteria for ASD—a nearly 60% increase.
Another important factor shaping autism statistics is the age at which diagnoses occur. Whereas children were once typically diagnosed between ages three and five, advances in screening protocols and broader awareness mean that many are now identified by age two—or even earlier in some cases.
Even today, geographic differences in diagnostic practices and screening intensity continue to drive variation in autism rates across the United States. For instance, California reports prevalence of 53.1 per 1,000 children, largely attributable to that state’s aggressive early screening and intervention programs. In contrast, Texas reports just 9.7 per 1,000, a 5.5-fold difference that cannot plausibly be explained by genetics or environment alone.
Kennedy has consistently promoted the theory that “environmental toxins” are driving autism increases, despite limited scientific evidence. At previous press conferences, he declared autism “a preventable disease” and insisted that “genes do not cause epidemics.”
However, research consistently shows that genetics play a major role in autism, with siblings of autistic children having 15 times greater likelihood of diagnosis and multiple genetic variants identified as contributing factors. While environmental factors may interact with genetic predispositions, no specific environmental toxin has been definitively linked to autism causation.
Ironically, a ProPublica investigation revealed that Kennedy has actually cut millions in federal funding for autism research, including studies on environmental causes, while promising to find autism’s origins. The report noted that Kennedy eliminated entire divisions studying workplace chemical exposures and their potential links to autism.
Trump also promoted long-debunked claims about vaccines and autism, recommending significant changes to childhood immunization schedules. He called for:
- Separating the measles, mumps, and rubella (MMR) vaccine into individual shots
- Removing mercury and aluminum from vaccines
- Delaying the hepatitis B vaccine until age 12 instead of administering it within 24 hours of birth
- Spacing out vaccine doses over longer intervals
“Don’t let them pump your baby full of the largest amount of stuff you’ve ever seen,” Trump said, acknowledging his recommendations were based on personal beliefs rather than medical evidence: “You know, I’m just making these statements from me… I talk about a lot of common sense.”
The scientific consensus is overwhelming and unequivocal: vaccines do not cause autism. This conclusion is supported by decades of rigorous research involving millions of children across multiple countries, extensive meta-analyses, and comprehensive reviews by leading medical institutions.
The vaccine-autism controversy originated with a fraudulent 1998 study by Andrew Wakefield that was later fully retracted by The Lancet after investigations revealed he had acted “dishonestly and irresponsibly,” falsified data, and received undeclared payments from lawyers pursuing vaccine lawsuits. Wakefield lost his medical license in 2010, yet his debunked claims continue to fuel vaccine hesitancy today.
Following his claims, researchers worldwide conducted extensive studies including a comprehensive 2014 meta-analysis of over 1.2 million children that found no relationship between vaccination and autism, and massive population studies like the Danish National Registry analysis of 537,303 children that showed no difference in autism risk between vaccinated and unvaccinated children.
Multiple specific hypotheses about vaccine-autism connections have been systematically disproven, including concerns about thimerosal (a mercury-containing preservative), temporal clustering of autism cases after vaccination, and multiple vaccine exposure. Notably, autism rates continued to rise even after thimerosal was removed from childhood vaccines by 2001, providing strong population-level evidence against any causal relationship.
The 2004 Institute of Medicine review, conducted by 15 independent experts who analyzed over 200 studies, concluded that epidemiological evidence “favors rejection” of causal relationships between both MMR vaccine and thimerosal-containing vaccines and autism.
