The CDC announced in 2000 that it was removing the chemical from most childhood vaccines ― a move that some doctors say may have given anti-vaccination groups a sense of legitimacy that wasn’t actually founded in medical fact.

The “rise in autism” that Green referenced is also misleading. One in 59 children in the U.S. were diagnosed with autism spectrum disorder as of 2018, compared to one in 68 in 2016, according to the CDC. But officials attribute this rise at least partially to improvements made in identifying and diagnosing the disorder, particularly in minority communities.

In a 2017 release responding to fears about the link between vaccines and autism, the American Academy of Pediatrics reiterated that such claims “have been disproven by a robust body of medical literature.”

“Delaying vaccines only leaves a child at risk of disease,” the AAP said.

Green will be sworn in on Jan. 3 as a freshman in the U.S. House of Representatives. He has previously received backlash for questionable comments, including a remark at a Tea Party event in 2016 that he believes being transgender “is a disease.”