US Health Secretary Robert Kennedy Jr. has intensified his controversial claims linking Tylenol use to autism, particularly in boys who undergo circumcision. Speaking at a cabinet meeting with President Donald Trump, Kennedy argued that circumcised boys are twice as likely to be diagnosed with autism, attributing this increased risk to the administration of Tylenol during or after the procedure.
Kennedy cited a 2015 study published in the Journal of the Royal Society of Medicine, which examined autism rates among Danish boys under 10 who had undergone circumcision. The study found higher autism prevalence among circumcised boys but did not track painkiller or anesthetic use, leaving any connection to Tylenol unproven. Researchers have emphasized that the study only shows a correlation, not causation, and subsequent research has found no evidence supporting a link between Tylenol and autism.
Despite the lack of conclusive evidence, Kennedy suggested that resistance to his claims was politically motivated, stemming from animosity toward Trump. The cabinet meeting remarks followed a prior controversy in September when Kennedy and Trump jointly advised pregnant women against using Tylenol, claiming its active ingredient, acetaminophen, could increase autism risk. Tylenol manufacturer Kenvue responded by reaffirming that scientific studies show no causal link between acetaminophen and fetal developmental issues.
Current medical guidelines continue to recommend acetaminophen as safe for use during pregnancy. The US Food and Drug Administration advises against ibuprofen after 20 weeks of gestation, while organizations such as the Society for Maternal-Fetal Medicine and the American College of Obstetricians and Gynecologists have endorsed acetaminophen use as recently as early September 2025.
In the cabinet meeting, Trump echoed Kennedy’s caution, advising against Tylenol use during pregnancy and for newborns. Kennedy, while acknowledging the absence of definitive proof, maintained that the evidence is suggestive enough to caution against its use, stating that taking the drug during pregnancy is “irresponsible.”
