Autism experts are strongly pushing back against claims from a Trump administration–era report suggesting that prenatal acetaminophen (Tylenol) use and vaccines may increase the risk of autism, and that an older drug could treat autism symptoms.

The report urged pregnant women to avoid acetaminophen and proposed reapproving leucovorin calcium as a treatment for autism. According to HHS Secretary Robert F. Kennedy Jr., the claims are based on studies suggesting possible neurodevelopmental risks.

However, autism researchers say those studies are not scientifically sound and do not support a causal link between autism and acetaminophen, vaccines, or leucovorin as an effective treatment.

Major medical organizations, including the American Psychological Association, warn that claims linking autism to vaccines have been repeatedly discredited in large, peer-reviewed studies. Experts also note that acetaminophen is one of the few safe, over-the-counter pain relief options available during pregnancy when used appropriately.

A large study published in JAMA examining 2.4 million children found no association between prenatal acetaminophen use and autism, ADHD, or intellectual disability.

Experts agree that autism is a complex neurodevelopmental condition influenced by multiple genetic and environmental factors, with no single known cause. Public health guidance, they stress, must remain grounded in evidence-based science.