The health and human services secretary, Robert F. Kennedy Jr.,  is zeroing in on a new potential culprit in the nation’s rapidly rising rate of autism – circumcision.

At a cabinet meeting on Thursday, the secretary said a pair of studies have found circumcised boys twice as likely as others to develop autism and suggested the missing link may be Tylenol administered as a painkiller to the newly circumcised children.

Mr. Kennedy did not address the fact that the number of autism diagnoses is rapidly rising in America at the same time the number of boys being circumcised is declining. Fewer than half of American boys were circumcised in 2022 compared to 54 percent in 2012, according to a study by Johns Hopkins University.

Mr. Kennedy announced last month that the government will issue new guidance related to acetaminophen, more commonly known by the brand name Tylenol. He said that doctors should not recommend use of the over-the-counter painkiller by pregnant women because of the possible link to autism.

The announcement met with strong pushback from the makers of Tylenol, which calls its product the safest painkiller for pregnant women when used as directed, and from doctors and scientists who insist there is no evidence of a causal link between the drug and the condition.

At his Cabinet meeting on Thursday, President Trump touted the partial peace agreement between Israel and Hamas. The president says he expects to travel to the region at the beginning of next week, when the first of the remaining Israeli hostages are due to be released from Gaza. 

Mr. Trump went on to ask if any members of the Cabinet would like to speak. The secretaries of state, defense, and the interior all spoke about the peace plan. Vice President Vance praised the president for his work as well. 

Mr. Kennedy, though, used his time to renew his warning about a potential link between autism and Tylenol. “It is so suggestive that anybody who takes this stuff during pregnancy, unless they have to, is irresponsible,” Mr. Kennedy declared. 

“It is not proven,” he said of his Tylenol claims. “We’re doing the studies to make it proven, but in the meantime, the precautionary principle should apply.”

When Mr. Trump asked Mr. Kennedy for more specifics, the health secretary pointed to the rapid growth in the number of autism diagnoses as a reason to intensely study the disorder and suggested  there could be a link between autism and circumcision. 

“There’s many, many other confirmation studies,” Mr. 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.”

“None of this is dispositive, but all of it is stuff we should be paying attention to,” he added. 

He appeared to be referring in part to a 2015 article in the Journal of the Royal Society of Medicine which studied circumcision and its possible link to autism. The study was conducted in Denmark and found some correlation between circumcision and autism spectrum disorder, though not enough to make any determination about whether it causes the condition. 

The Denmark study did not examine acetaminophen because the authors had “no data available” about what anaesthetics — if any — were used for young boys who were circumcised. They noted  that a hypothesis put forward by fellow scientists “obtained only limited empirical support” for such a link. 

One British psychologist and professor, Jeremy Turk, told the Science Media Centre at the time that the results of the study were “interesting,” but said no one should draw any conclusions from it. 

The findings of this research “need to be considered carefully — one cannot draw very strong conclusions from the data. This is not a causal study, but instead compares data sets and looks for correlations. Whilst this is a valid way of doing a study, it means that we must be careful about any implications.”

The manufacturer of Tylenol, Kenvue, has similarly argued against claims that acetaminophen is a driver of increased autism risks. 

“Acetaminophen is also one of the most widely studied pain relievers and fever reducers in infants and children, and numerous randomized, controlled clinical trials support the safety of acetaminophen in infants and children when used as directed,” a spokesman for Kenvue, Pat Rose, told the New York Sun in a statement. 

“The facts are that over a decade of rigorous research, endorsed by leading medical professionals and global health regulators, confirms there is no credible evidence linking acetaminophen to autism,” Mr. Rose added.