New York, NY (September 22, 2025) – The Autism Science Foundation (ASF) has expressed serious concern regarding today’s announcements from President Trump and HHS Secretary Robert F. Kennedy, which suggested links between acetaminophen (Tylenol) use during pregnancy and autism, proposed leucovorin as a treatment for autism, and recommended altering childhood vaccine schedules.
“Any association between acetaminophen and autism is based on limited, conflicting, and inconsistent science and is premature,” said Dr. Alycia Halladay, Chief Science Officer at ASF. “This claim risks undermining public health while misleading families who deserve clear, factual information. For years, RFK and President Trump have shared the belief that vaccines cause autism, which is not supported by scientific evidence.”
Alison Singer, President of ASF, added: “No new data or studies were presented. Instead, personal opinions were offered, suggesting dangerous guidance, such as avoiding Tylenol or spacing out vaccines. This echoes outdated and harmful ideas that blame mothers for autism, which is simply shocking.”
Risks of Misleading Claims
“Today’s statements downplay autism’s complexity and suggest it could be prevented by stopping acetaminophen use or altering vaccine schedules,” said Dr. Halladay. “These claims ignore established public health practices and distract from urgent research needed to understand autism and provide supports for autistic people and their families.”
See more of our coverage in your search results.
Add Hunterfly on GoogleAutism arises from a complex interaction of genetics and environmental factors. Hundreds of genes have been linked to autism, with environmental influences—such as parental age, prematurity, low birth weight, or fever during pregnancy—also playing a role. ASF emphasizes that genetic susceptibility is the primary factor, and autism does not have a single cause.
Acetaminophen and Autism
The cited studies on acetaminophen involve six studies with inconsistent results. Relative risk ratios were not sufficient to indicate causation, and confounding variables, including genetics and the reason for acetaminophen use, were often not controlled. Fever during pregnancy, for instance, is a known risk factor for autism, and acetaminophen is often used to reduce fever.
Notably, a large Swedish study of 2.4 million children using sibling controls found no association between prenatal acetaminophen and autism once genetic and maternal health factors were considered. Similar findings were reported in a Japanese sibling-control study.
According to current guidelines from the American College of Obstetricians and Gynecologists, acetaminophen remains a safe method for treating pain and fever during pregnancy when used appropriately.
Leucovorin and Autism
Leucovorin (folinic acid) has been suggested as a treatment for autism, but evidence comes from four very small, inconsistent trials, often reliant on specific genetic variants. ASF states that this research is preliminary and not sufficient to recommend leucovorin as a treatment. More rigorous studies are needed before any definitive conclusions can be drawn.
See more of our coverage in your search results.
Add Hunterfly on GoogleConclusion
ASF strongly supports research into autism’s causes but warns against alarming families with incomplete or misleading claims. Pregnant women and caregivers deserve clear, evidence-based guidance. “The best science shows that autism arises from a complex interplay of genetic and environmental factors. Families should rely on medical advice and proven public health practices,” added Dr. Halladay.
