One challenge is that it’s hard to disentangle the effects of Tylenol use from the effects of high fevers during pregnancy. Trump also urged not giving Tylenol to young children, but scientists say that research indicates autism develops in the fetal brain. Responding to Trump’s warnings, the Society for Maternal-Fetal Medicine said it still recommends Tylenol as an appropriate option to treat fever and pain during pregnancy. The theory is that some, not all, children with autism may not properly metabolize folate, Mandell said. For some people, profound autism means being nonverbal and having intellectual disabilities, but the vast majority of people with autism experience far milder effects.