On Monday, President Donald Trump claimed that taking Tylenol (acetaminophen) during pregnancy can cause autism in babies. His comments were met with swift criticism, including from former President Barack Obama, who said Trump’s remarks “undermined public health.”

Trump suggested that people who don’t take vaccines or pills have “no autism” and asked U.S. Health Secretary Robert F. Kennedy Jr. if his statements were true. He added that ideally, pregnant women should avoid Tylenol, but if necessary, they might have to take it.

The World Health Organization responded by stating there is currently no conclusive scientific evidence linking acetaminophen to autism. WHO noted that autism spectrum disorder affects about 62 million people worldwide and is caused by multiple factors that are still not fully understood.

At an event in London, Obama called Trump’s comments “violence against the truth,” warning they could scare pregnant women and hinder autism research. He explained that increases in autism diagnoses are largely due to better awareness and improved diagnostic criteria.

Tylenol’s manufacturer also issued a statement affirming the drug is “one of the most studied in history” and safe when used as directed by expecting mothers. They emphasized over a decade of research found no credible link between acetaminophen and autism and that it remains the recommended first-line treatment for pain and fever during pregnancy.

Tylenol representatives advised pregnant women to consult their doctors, reminding them that untreated high fevers and pain can be dangerous, especially in the first trimester.