“Taking Tylenol is not good. I’ll say it. It’s not good,” Trump said.

Michigan State University autism researcher and board-certified geneticist Andrea Amalfitano studies autism and its causes. The claims about acetaminophen target a "fraction of a fraction of cases in autism," and fail to look at the broader picture, he said. 

In his book, "Autism Revealed: Clarity Through Understanding Its Causes," Amalfitano examines the numerous studies conducted to identify the causes of autism. "We already know a lot," he said — "and in most cases, up to 90%, the cause is genetic."

“Focusing on environmental things that are very, very low likelihood of being a cause, let alone an association, like Tylenol, diverts us from really thinking about the true known causes of autism,” Amalfitano said. 

Many experts and physicians have voiced similar concerns since the information was released, questioning the strength of the research and evidence used to support the decision. 

In a press release, the Department of Health and Human Services, or DHHS, cited a Harvard study to justify the change in labeling. That study, however, identifies only an association between Tylenol and autism — not a direct causal relationship. 

Deputies at Monday's press conference also said leucovorin could be used as a potential treatment for cerebral folate deficiency and autistic symptoms: a claim that will now be reflected on the drug's labeling.

But that statement is also being challenged by researchers. There are very few studies examining the impact of leucovorin on autism, and the existing research is far from conclusive, Amalfitano said. 

The American Psychiatric Association issued a statement Monday, cautioning that many more years of research are needed “before we know if leucovorin is an appropriate treatment for individuals with autism.”

DHHS also acknowledged the uncertainty in its press release, noting that leucovorin "is not a cure for Autism Spectrum Disorders, or ASD, and may only lead to improvements in speech-related deficits for a subset of children with ASD.”

MSU researchers say the administration's comments have already caused confusion and concern.

Professor of Clinical Psychology and director of the MSU Autism Lab, Brooke Ingersoll, said her colleagues have already heard from families inquiring about leucovorin as a treatment option. 

“I think it's going to impact the level of trust that families and the community in general have in both government and in research,” Ingersoll said. 

The Autism Lab primarily focuses on the development, evaluation and implementation of intervention programs for parents of young children with autism. The goal is to “improve core symptoms and core challenges in autism,” and implement these programs into community systems, Ingersoll said. 

Associate Professor Sarah Douglas in the Department of Human Development and Family Studies also serves as director of the research in the Autism and Developmental Disability Lab, which conducts research to support children with disabilities, their families and their educational teams. Much of the information released by the Trump administration regarding autism could impact her work. 

“We have lots of evidence-based practices that tell us what works for children with autism,” Douglas said. “If we abandon those practices in favor of finding what people might purport as a cure, we're doing a huge disservice to the families and the children we already have who have these needs.”

The rising number of autism diagnoses is at the center of the Trump administration's focus. DHHS Secretary Robert F. Kennedy Jr. called the trend an epidemic, noting that 1 in 31 children in the U.S. are now affected. 

“For too long, families have been left without answers or options as autism rates have soared,” Kennedy said during the press conference. 

But those numbers don't necessarily indicate a crisis, Amalfitano said, noting that expanded diagnostic criteria and increased screening have led to higher reported rates.

“If you’re going to broaden the criteria ... you’re going to have more and more people falling under that umbrella,” Amalfitano said. 

The rhetoric of crisis deepens stigma and shifts attention away from how autism is understood and supported, Ingersoll said. Douglas said that recognizing autism as a form of diversity is essential to that understanding. 

“This is not a disease, this is a natural form of diversity,” Douglas said. “Yes, we know that there are some people with autism who have a lot of needs. And certainly, we want to come up with solutions to help those individuals, but just because a person has autism doesn't mean that they have no hope.”