Health Secretary Robert F. Kennedy Jr. is facing scrutiny after reports suggested he may soon announce a possible link between autism and Tylenol use during pregnancy. The claim, first reported by The Wall Street Journal, would challenge decades of medical guidance that has considered acetaminophen—the active ingredient in Tylenol—to be one of the safest options for pain relief while pregnant.
Kennedy has hinted for months that he would identify the “cause” of autism by September. According to the Journal, the announcement could also include other theories, such as low levels of folate in pregnancy. Officials at the Department of Health and Human Services (HHS), however, urged caution. A spokesperson said that no final conclusions had been reached and that “gold-standard science” is being used to examine the issue.
Market and Political Reactions
The report had immediate ripple effects. Shares of Kenvue, the maker of Tylenol, fell more than 9% on Friday after the story broke. Meanwhile, political allies and figures close to the Trump administration fanned speculation earlier in the week, with activists and advisers suggesting acetaminophen and vaccines could be tied to autism—a theory long discredited by mainstream science.
What the Science Says
Researchers have spent decades examining whether acetaminophen poses risks during pregnancy. The overwhelming body of evidence shows no causal link between the drug and autism.
One of the largest studies to date, published last year in JAMA, followed families where one sibling had been exposed to acetaminophen in the womb and another had not. Researchers found no increased risk for autism, ADHD, or intellectual disability when comparing siblings—suggesting that previous associations in population-wide data may have been influenced by other factors.
Dr. Joshua Gordon, a psychiatrist and neuroscientist at Columbia University, said that while small, less rigorous studies occasionally raise questions, large, well-controlled research consistently points to “low to non-existent” risk. “RFK Jr. and those he supports have a long history of ignoring very large-scale studies,” he said, while promoting less reliable findings.
Conflicting Reviews
The controversy has been reignited by a recent review in BMC Environmental Health suggesting a “likely association” between prenatal acetaminophen use and autism. But experts caution that the review was not as robust as the JAMA study and failed to account for genetic and environmental factors that play central roles in autism risk.
“If acetaminophen were a major driver, autism rates would be dramatically higher,” said Santhosh Girirajan, a neurodevelopmental researcher at Pennsylvania State University. Instead, most scientists agree that autism has multiple contributing factors—many of them genetic.
Guidance for Pregnant Patients
Doctors emphasize that pregnant people should not panic. Dr. Christopher Zahn of the American College of Obstetricians and Gynecologists reiterated that acetaminophen remains the safest recommended pain reliever during pregnancy. “Unfortunately, over the years, there have been several unfounded challenges to this fact, which have likely caused some confusion and concern,” he said.
Autism, which the CDC estimates affects 1 in 31 U.S. school-aged children, is a spectrum of developmental conditions with diverse causes and manifestations. The search for a single “cause,” experts say, oversimplifies a complex condition.
As Kennedy’s announcement approaches, researchers urge families to rely on established evidence rather than speculation. For now, acetaminophen continues to be considered safe during pregnancy, and medical organizations are standing firmly by that guidance.
