President Donald Trump says his administration has an “answer to autism.” At a White House press conference on Monday, the president, joined by Health and Human Services Secretary Robert F. Kennedy Jr., linked autism to acetaminophen, the active ingredient in Tylenol, when taken during pregnancy. Trump advised pregnant women to “fight like hell not to take it” except in extreme cases. They argue that the causes of autism are complex and multifaceted. This episode: What do we actually know about the causes of autism? And are we, as President Trump claims, in the midst of an “autism crisis”?