US President Donald Trump and Health Secretary Robert F. Kennedy Jr. on Thursday promoted a fringe theory linking autism to circumcision or pain medication given during the procedure.

“Don’t take Tylenol if you’re pregnant and when the baby is born, don’t give it Tylenol,” Trump said at a Cabinet meeting. Kennedy added, “There’s two studies that show children who are circumcised early have double the rate of autism. It’s highly likely because they’re given Tylenol.”

Experts dismissed the claims. Helen Tager-Flusberg, Boston University autism expert, told AFP: “None of the studies have shown that giving Tylenol to babies is linked to a higher risk for autism once you can control for all the confounding variables.”

Medical guidance advises pregnant women can take pain medication like acetaminophen in moderation. While a few studies hinted at associations, no causal link has been proven. The most rigorous analysis, published in JAMA last year using siblings as controls, found no connection.

The circumcision theory also lacks support. David Mandell, psychiatrist at the University of Pennsylvania, said the widely cited 2015 Danish study “was riddled with flaws,” relying on a tiny sample of hospitalized Muslim boys rather than the typical home-based circumcisions. “A more recent review of studies in this area finds no association between circumcision and any adverse psychological effects,” he added.

Kennedy, a former environmental activist and vaccine misinformation advocate, has focused on autism causes while cutting other research grants. He has hired David Geier, a vaccine conspiracy theorist previously disciplined for unlicensed medical practice, to investigate vaccine-autism links, which have been repeatedly debunked.