Kenvue shares tumbled more than 10% on Friday after a Wall Street Journal report revealed that Health and Human Services Secretary Robert F. Kennedy Jr. plans to link prenatal use of Tylenol, one of the company’s best-selling products, to autism in an upcoming federal report, a move that has rattled investors.
Kennedy is reportedly preparing to release a federal report asserting that acetaminophen use during pregnancy and folate deficiency are potential contributors to autism, and that folinic acid (leucovorin) may offer therapeutic benefits for symptom relief.
Kennedy at Senate hearing yesterday. From hearing livestream.
Kenvue, which was spun out from Johnson & Johnson in 2023, saw its shares dip more than 10% in late-day trading following the report. Acetaminophen, also known as paracetamol, has been used clinically since 1950. Johnson & Johnson debuted Tylenol in 1955. It is now marketed by the Kenvue division McNeil Consumer Healthcare. The company’s self care segment, which includes Tylenol, brought in $1.55 billion in Q2 2025, representing approximately 40.5% of total quarterly revenue ($3.84 billion).
Prior studies have not shown a firm connection between Tylenol use in pregnancy and autism. In fact, a 2024 JAMA sibling control study involving 2.48 million Swedish children found that while simple models showed slightly elevated risk, analyses comparing full siblings controlled for familial confounding revealed no increased risk.
NIH-supported commentary in 2024, citing the same JAMA study, aligns with the notion that there is little evidence supporting a causal effect of prenatal acetaminophen on autism risk once confounding factors are considered.
Still, observational studies have continued to fuel debate. In the Boston Birth Cohort (n=996), newborns in the highest tertile of acetaminophen-related cord biomarkers had roughly 2.9× higher odds of ADHD and about 3.6× higher odds of an ASD diagnosis versus the lowest tertile, an exposure–response pattern that is associational and not proof of causation. At the same time, professional guidance has not shifted: the American College of Obstetricians and Gynecologists continues to identify acetaminophen as appropriate in pregnancy when used as directed (lowest effective dose, as needed, in consultation with a clinician).
This is not the first time Kennedy has claimed to know the cause of autism. He has previously claimed that mold, vaccines, and ultrasounds cause the disorder, which he also falsely referred to as a “preventable disease.” Researchers have linked autism, in part, to environmental and genetic factors.
203 days in office
A report from Senators Wyden and Alsobrooks released Thursday details Kennedy’s actions in his first 203 days in office. Mar. The report states that Kennedy had “lengthy meetings” with UFC fighter Conor McGregor to discuss the nonexistent link between “autism and vaccines” in March. Numerous peer-reviewed studies have debunked any connection between autism and vaccines.
The report also details that Kennedy “appointed a famed vaccine conspiracy theorist, David Geier, to lead a federal study into the relationship between immunizations and autism”. Geir and his father have published papers linking vaccines to autism. In 2011, Grier was charged with practicing medicine without a license.
The argument that vaccines are correlated with autism is tied to Andrew Wakefield, who penned a 1998 article in The Lancet, which was eventually retracted, based on a study involving 12 children with chronic enterocolitis and regressive developmental disorder. Wakefield lost his medical license in the UK after facing charges of “serious professional misconduct.”
