This week, a number of medical organizations and some lawmakers expressed concern after President Donald Trump and Health and Human Services Secretary Robert F. Kennedy Jr. addressed the supposed link between autism and acetaminophen, which is the active component in Tylenol.
A common response from critics was to counter an argument that Trump’s administration hadn’t even made—namely, that acetaminophen directly causes autism.
For instance, the American College of Obstetricians and Gynecologists reiterated that after over 20 years of research, no credible study has found that using acetaminophen during pregnancy leads to neurodevelopmental disorders in children.
Of course, many are worried about the apparent correlation rather than a direct cause and effect between using Tylenol during pregnancy and autism, a connection that various studies in respected peer-reviewed journals have supported.
Research from sources like Environmental Health, JAMA Psychiatry, and Clinical and Experimental Pediatrics has contributed to this discussion.
This kind of research doesn’t seem to faze an organization that’s generally supportive of the pharmaceutical industry, but it has raised concerns within the company that has produced Tylenol for decades.
Johnson & Johnson first made Tylenol, an acetaminophen product, available over the counter in 1960. In 2023, the company spun off its consumer healthcare division, Kenvue, which now manufactures it independently.
Recent internal documents reportedly reveal that years before their breakup with Tylenol, some senior scientists at J&J acknowledged the potential association between Tylenol use and autism.
For example, in 2018, Rachel Weinstein, then the U.S. Director of Epidemiology at Janssen (a J&J division), noted in an email her growing concerns regarding the evidence linking acetaminophen and autism. In that communication, she referred to a study published in the International Journal of Autism Research, indicating that prolonged maternal use of acetaminophen during pregnancy might correlate with increased autism spectrum disorders in children.
The company’s documents were provided to a law firm leading class action lawsuits against Kenvue and retailers selling generic acetaminophen products.
“This email shows that the company’s public stance is simply spin,” stated Ashley Keller, an attorney involved in the class action case set to be heard in the Second Circuit Court of Appeals. “Internally, they were aware of the growing scientific evidence linking prenatal Tylenol use to neurodevelopmental harm in children,” Keller added.
Weinstein had previously expressed the weight of the evidence to a researcher, commenting on the strengths of various studies, published in JAMA Pediatrics, which suggested a heightened risk for ADHD and similar behaviors linked to maternal acetaminophen use.
They considered following up on this research, but Weinstein seemingly hesitated, questioning whether they should “stick their necks out” on the issue.
An internal presentation labeled “Privilege and Confidential” in 2018 examined studies that suggested a connection between Tylenol and various neurodevelopmental disorders. It noted that many papers indicated consistent associations between prenatal acetaminophen exposure and adverse developmental outcomes.
Moreover, previous scientific reviews have shown an increased risk of negative prenatal neurodevelopment effects tied to acetaminophen use.
Keller emphasized that there are multiple reliable studies backing these claims and stated, “There are many studies showing links between Tylenol and neurodevelopmental harm in children…” While the causal relationship might not be definitively established, she believes that even the possibility of risk warrants caution.
In response to inquiries, a J&J spokesperson reminded the public that the consumer health division sold its assets years ago and stated that Kenvue retains all rights and responsibilities concerning Tylenol. Kenvue continues to reject any claims linking its product to autism, insisting there is no causal relationship.
Keller, representing families in the class action, countered this assertion, noting numerous reliable studies that prompt serious concern about the potential risks of acetaminophen use in pregnancy.
She highlighted that while a definitive causal link hasn’t been established, the available evidence suggests a reasonable level of concern. She believes it’s important to warn pregnant women of potential risks even in the absence of conclusive proof.
