President Donald Trump says he has “the answer to autism” and plans to reveal those findings in a highly anticipated report during a Sept. 22 afternoon White House event.

The report comes after Health and Human Services Secretary Robert F. Kennedy Jr. vowed to find the cause of rising autism cases by September 2025, and is expected to list Tylenol as a possible cause.

"We're going to have an announcement on autism on Monday," Trump said on Sept. 20 at a dinner hosted by the conservative American Cornerstone Institute. "I think it's going to be a very important announcement. I think it's going to be one of the most important things that we will do."

He also mentioned the report during a memorial rally on Sept. 21 for conservative activist Charlie Kirk, who was killed Sept. 10 while speaking to a crowd at Utah Valley University, in Orem, Utah.

“I think you’re going to find it to be amazing,” Trump told a memorial rally for Charlie Kirk in Glendale, Arizona, on Sept. 21. "I think we found an answer to autism."

Acetaminophen, often sold under the brand name Tylenol, has long been considered the safest option for managing headaches, fever and other pain during pregnancy.

Large surveys have reported that between 40% and 65% of pregnant women use acetaminophen at some point during their pregnancy, according to the Society for Maternal-Fetal Medicine.

By 2022, the U.S. autism rate in 8-year-olds was 1 in 31, or 3.2%, up from 2.77% in 2020, 2.27% in 2018 and 0.66% in 2000, according to the Centers for Disease Control and Prevention.

Kennedy has asserted that the U.S. is in the grip of an "autism epidemic" fueled by "environmental toxins." Decades of research have not yielded firm answers on what contributes to autism, but many scientists believe genetics, potentially in combination with environmental influences, play a role. They also say the rising incidence of autism could be attributed to increased access to diagnostic tools and improvements in early detection.

A large study encompassing over 100,000 participants found that higher-quality studies tended to find a link between acetaminophen use during pregnancy and neurodevelopmental disorders in children, according to the report published Aug. 14 in BMC Environmental Health.

“Given the widespread use of this medication, even a small increase in risk could have major public health implications," said study author Dr. Diddier Prada, assistant professor of population health science and policy, and environmental medicine and climate science at the Icahn School of Medicine at Mount Sinai.

More than two dozen studies around the world have linked a pregnant person's frequent use of acetaminophen to autism and attention-deficit hyperactivity disorder, or ADHD, in their child. But several studies have also found competing evidence.

A 2024 study in Sweden of about 2 million children, over 180,000 of whom were exposed to acetaminophen during pregnancy, found no associations between the pain medication and children’s risk of autism, ADHD or intellectual disability.

Some researchers say the data isn’t so cut and dry. Many health conditions that cause pain or a fever, commonly treated with Tylenol, are also associated with an increased risk of autism and other neurodevelopmental disorders. For example, the 2024 Sweden study found that parents with "higher acetaminophen use" also tended to have more diagnoses of psychiatric or neurodevelopmental disorders, were more likely to smoke or take other medications.

"Results suggested that there was not one single 'smoking gun' confounder, but rather that multiple birthing parents’ health and sociodemographic characteristics each explained at least part of the apparent association," study authors said.

It’s difficult to detangle the data of what’s behind the link: Is it the Tylenol or these health conditions?

Kenvue, the makers of Tylenol, said acetaminophen continues to be the safest pain-relieving option for pregnant women and, without it, women are in danger of suffering a potentially harmful fever or using riskier alternatives to alleviate pain.

“We believe independent, sound science clearly shows that taking acetaminophen does not cause autism. We strongly disagree with any suggestion otherwise,” said company spokesperson Melissa Witt. “The facts are that over a decade of rigorous research, endorsed by leading medical professionals and global health regulators, confirms there is no credible evidence linking acetaminophen to autism.”

Autism spectrum disorder, or ASD, is the clinical name for the condition most people refer to as autism. Autism is defined as "a complex developmental condition that affects communication, social interaction and behavior," Christopher Banks, president and CEO of the Autism Society of America, told USA TODAY in April.

“At this time, the weight of scientific evidence that acetaminophen use during pregnancy causes an increased risk for autism or ADHD is simply inconclusive,” SMFM President Sindhu K. Srinivas said in a Sept. 5 statement. “In maternal-fetal medicine, as in all of medicine, our recommendations are based on an evaluation of rigorous research and data, clinical expertise, and our patients’ values and preferences.”

Contributing: Jeff Mason, Phil Stewart, Valerie Volcovici and Katharine Jackson, Reuters.

Adrianna Rodriguez can be reached at adrodriguez@usatoday.com.

This article originally appeared on USA TODAY: Tylenol, pregnancy and autism: Trump has his 'answer' but what does the science say?

Reporting by Adrianna Rodriguez, USA TODAY / USA TODAY

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