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President Donald Trump recently announced a breakthrough linking autism to the use of OTC pain and fever reducer Acetaminophen (Tylenol) during pregnancy.

Trump announced the autism link during a press conference at the White House on Monday.

The president warned against the use of Tylenol during pregnancy. He said that pregnant women should “fight like hell” to only take Tylenol in cases of high fever.

Photo of Tylenol

“Taking Tylenol is not good — I’ll say it: It’s not good,” Trump said. He also suggested that vaccines (such as mRNA vaccines) may cause autism.

Trump admin officials pointed to a study by Harvard University that shows pregnant women who took Tylenol had a slightly higher chance of giving brith to a child who was later diagnosed with autism.

Dr. Ann Bauer, one of the researchers in the study, said she believes the Trump administration jumped the gun.

“I’m a little concerned about how this message is going to come because I think they may be jumping the gun,” Bauer said before Trump’s press conference. “I think those of us in the research community would like to see stronger evidence.”

Doctors around the world and the makers of Tylenol immediately pushed back on Trump’s claims.

In a statement to NPR, Tylenol-maker Kenvue strongly disagreed with Trump’s claims on Monday.

“We believe independent, sound science clearly shows that taking acetaminophen does not cause autism,” the statement read. “We strongly disagree with any suggestion otherwise and are deeply concerned about the health risks and confusion this poses for expecting mothers and parents.”

Tylenol’s stock plummeted and lost 25% of its value in the hours after Trump’s announcement.

The stock rebounded after hours.