In May 2026, a claim (archived) circulated online that U.S. Health and Human Services Secretary Robert F. Kennedy Jr. said children who are circumcised early have double the rate of autism.
Autism is a complex neurodevelopmental condition that doesn't have a single known cause. Researchers currently believe autism develops from a combination of genetics and environmental factors.
Circumcision is the surgical removal of the foreskin from the penis and is usually performed in the first few days after a child is born. Children get circumcised for medical, religious and cultural reasons as well as for personal preference.
A Facebook user shared footage that appeared to show Kennedy making the claim and wrote, "Are you kidding me????? Let's FACT CHECK THIS......"
The claim also circulated on X (archived), Threads (archived) and Bluesky (archived).
The White House's official livestream of the meeting on YouTube showed that during an Oct. 9, 2025, Cabinet meeting, Kennedy said, "There's two studies that show children who are circumcised early have double the rate of autism and it's highly likely because they're given Tylenol." He continued, "So, you know, none of this is positive but all of it is stuff that we should be paying attention to." Kennedy himself confirmed (archived) this quote on his X account. Therefore, we find the statement to be correctly attributed.
Some of the claims that circulated in May 2026 used footage from the C-SPAN broadcast of the Oct. 9 Cabinet meeting. In that broadcast, Kennedy made the claim at time code 52:59.
Study alleged 'mishandling' of evidence
Kennedy said on his X profile that his Oct. 9 statement referred to a 2025 research paper titled "Evidence That Acetaminophen Triggers Autism in Susceptible Individuals Has Been Ignored and Mishandled for More than a Decade." At that time, the paper's authors had published it on Preprint.org, a site that hosts research papers before they are peer-reviewed or published online by journals.
By May 2026, the study had been peer-reviewed and published by the Journal of the Academy of Public Health, a journal founded by Jay Bhattacharya, the Trump-nominated director of the National Institutes of Health, and former Harvard University biostatistician Martin Kulldorf.
Bhattacharya and Kulldorf previously worked together on the Great Barrington Declaration, which argued against lockdowns during the early days of the COVID-19 pandemic.
Their journal faced early criticism for unusual editorial policies, such as only publishing articles submitted by the newly-formed Academy of Public Health and paying peer reviewers.
The 2025 study reviewed research papers on PubMed about autism and acetaminophen (best known by the brand name Tylenol) or paracetamol (another name for acetaminophen) and the link between them. It found that the scientific community had "mishandled" earlier studies in the field through "misinterpretation" of data. "Irrational criticisms" of papers in the field also played a role in their mishandling, according to the study.
The study concluded: "Available evidence is already more than sufficient to establish a causal relationship between acetaminophen and autism, and resolution of the problem need not wait on additional studies."
One of the studies the preprint paper cited as "some of the most compelling 'standalone' evidence that acetaminophen is a developmental neurotoxin" was a 2015 peer-reviewed study that compared circumcised and uncircumcised boys from Denmark up to 9 years old. That study found that circumcised boys up to 4 years old were twice as likely to develop infantile autism as their uncircumcised peers but pointed to circumcision rather than acetaminophen exposure as the trigger.
The 2025 study also referenced a 2013 peer-reviewed study that suggested that a rise in circumcision rates "was associated" with a rise in autism spectrum disorder diagnoses across the nine countries it studied. It also suggested that autism prevalence in those countries rose after more doctors started using acetaminophen in circumcisions in 1995.
Criticism of studies
Both the 2013 and 2015 studies faced various criticisms. Critics of the 2015 study noted its small sample size (according to the 2015 study, 57 autism spectrum cases in "ritually circumcised" boys and 4,929 cases in intact boys) and that the study only found a significant increased risk of autism in boys 4 and younger.
The 2013 study faced similar criticism for its nine-country sample size. Helen Tager-Flusberg, a Boston University professor emeritus who sits on the executive board of the Coalition of Autism Scientists — a group that advocates for high-quality research into the condition — told Scientific American that the 2013 study failed to consider any factors besides acetaminophen use to account for a rise in autism prevalence.
Genetic factors and the age of a child's parents can affect autism rates as well as methods and resources for diagnosis.
Both studies said their findings established correlation rather than causation, meaning that the 2013 study did not claim that higher rates of acetaminophen use in children caused autism diagnoses to rise, nor did the 2015 study claim that circumcisions caused autism diagnoses in children who had the procedure. Both studies also said larger-scale research was needed, something the preprint study claimed was unnecessary.
Morten Frisch, one of the 2015 study's authors, also co-submitted a citizen's initiative to raise the legal minimum age for circumcisions of otherwise healthy children to 18. Danish politicians did not pass the resulting bill. Frisch declared a competing interest in the 2015 study. William Parker, a co-author on the preprint study Kennedy cited, has published multiple articles on the suspected link between autism and acetaminophen. Parker was reportedly in frequent communication with Kennedy and other health officials in the U.S., according to a September 2025 interview in The Atlantic.
Trump has tasked Kennedy with investigating the rise in national autism rates. In the Oct. 9 Cabinet meeting, Trump and Kennedy both repeated a largely unsupported theory that taking Tylenol during pregnancy could increase a child's risk of being diagnosed with autism.
For further reading, Snopes has reported extensively on Tylenol's suspected link to autism after Trump began repeating the unsupported claim.