“We heard the president say that women should tough it out,” says Amaral. “I was really taken aback by that, because we do know that prolonged fever, in particular, is a risk factor for autism. In particular, Gardner points out that pregnant women needing to take Tylenol are more likely to have pain, fevers, and prenatal infections, which are themselves risk factors for autism. Using health records from nearly 2.5 million children in Sweden, they reached the opposite conclusion to the president: Tylenol has no link to autism. Another major study of more than 200,000 children in Japan, published earlier this month, also found no link.