Another study, same result: no link between Tylenol use during pregnancy and autism. This one was massive — over 124,000 sibling-matched children.
The researchers used a sibling-matched design, which controls for genetics and shared environmental factors. That’s important because previous studies that found an association didn’t account for those variables properly.
When the team compared acetaminophen-exposed kids to unexposed ones without the sibling match, they saw a link — same as some older studies. But when they ran a negative control (comparing moms who took Tylenol before pregnancy or after birth), that same association appeared. Which is biologically impossible. That tells you the signal was family background, not the drug.
No link to ADHD either. The ADHD analysis covered over 97,000 sibling-matched children. Same result across dosage, timing, trimester, and maternal age.
This isn’t the first study to reach this conclusion. Large sibling-matched studies in Sweden (2024) and Japan (2025) found the same thing.
Still, Trump and RFK Jr. held a press conference in September claiming without evidence that acetaminophen causes autism. Trump told pregnant women to “tough it out” with fever. Medical groups pushed back hard — untreated fever during pregnancy is known to increase autism risk, along with risks of miscarriage, birth defects, and premature birth.
The impact was real though. A Lancet study found acetaminophen use in emergency departments dropped 10% after that press conference. Texas even sued the maker of Tylenol.
Science says there’s no link. The politics say otherwise.
