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Updated September 24, 2025, at 11:44 a.m.
Harvard School of Public Health Dean Andrea A. Baccarelli received at least $150,000 to testify against Tylenol’s manufacturer in 2023 — two years before he published research used by the Trump administration to link the drug to autism, a connection experts say is tenuous at best.
Baccarelli served as an expert witness on behalf of parents and guardians of children suing Johnson & Johnson, the manufacturer of Tylenol at the time. U.S. District Court Judge Denise L. Cote dismissed the case last year due to a lack of scientific evidence, throwing out Baccarelli’s testimony in the process.
“He cherry-picked and misrepresented study results and refused to acknowledge the role of genetics in the etiology” of autism spectrum disorder or ADHD, Cote wrote in her decision, which the plaintiffs have since appealed.
Baccarelli, who was a professor at Columbia University’s public health school at the time, declined to comment on his involvement in the case.
The plaintiffs paid Baccareli $700 an hour for his expert testimony, according to a 2023 deposition.
“I work for more than 200 hours, so it’s about $150,000,” Baccarelli said in the deposition.
But Catherine E. Lord — a professor of Psychiatry and Education at the University of California, Los Angeles — said it is not uncommon for medical professionals to be paid for expert testimony.
“People are routinely paid, and they’re paid generally quite a lot,” Lord said. “There are people who, for as a job, testify as experts.”
“I think what it does suggest, given that he would testify about this, that he is invested in finding something more than most of us would be,” Lord said.
In a statement to the New York Times, HSPH spokesperson Stephanie Simon wrote that Baccarelli “confirmed that his testimony in the deposition was accurate and that his work on the case culminated in the deposition; he worked just a handful of additional hours following the deposition.”
Trump administration officials have trumpeted Baccarelli’s work as evidence that acetaminophen — the active ingredient in Tylenol — causes autism.
“To quote the dean of the Harvard School of Public Health,” Food and Drug Commissioner Marty A. Makary said in a press conference on Monday, “there is a causal relationship between prenatal acetaminophen use and neurodevelopmental disorders of ADHD and autism spectrum disorder.”
Though the study the Trump administration latched onto is a more recent paper, published in August, and Baccarelli has studied the subject for years, scientists say his work has demonstrated only a correlation between the drug and autism — and not a causal link, as the Trump administration asserted in the press conference.
Baccarelli’s published statement to the White House only referred to the “possibility of a causal relationship” between acetaminophen and autism. In both his statement and the August paper, Baccarelli called for further study.
His work rocketed into public view after the press conference on Monday, which took place weeks after he met with Health and Human Services Secretary Robert F. Kennedy Jr. ’76 and Jay Bhattacharya, the director of the National Institutes of Health, on phone calls to discuss his recent research.
Baccarelli’s recent survey of 46 human studies, published online in August alongside three coauthors, concluded that prenatal acetaminophen usage was associated with increased incidence of neurodevelopmental disorders — including autism and attention deficit hyperactivity disorder. Experts believe that so far, the evidence only shows a correlation.
“The idea that acetaminophen causes autism is, at best, a massive overstatement and might be completely untrue,” Samuel S. Wang, a professor of neuroscience at Princeton University, said.
“The best study to date that I’ve been able to see in the literature shows no additional risk,” he added.
A 2024 study in the Journal of the American Medical Association involved 2.5 million children born in Sweden, and controlled for compounds across these millions of samples. The research determined that there was no causal relationship between acetaminophen consumption and autism.
“There needs to be much more work done and additional studies to be able to identify causal mechanisms,” Dennis P. Wall, professor of Pediatrics and Biomedical Data Science at Stanford University, said. “That simply hasn’t been done.”
Lord said that she would not fault Baccarelli or the other authors for the study.
“I just think that to take it the next step and say this is causal, is really irresponsible,” she added.
Wang said that there is a “consensus view of what causes autism” within the scientific community. Genetic inheritance, combinations of genes, environmental causes, stresses in mid to late pregnancy, and other biological factors all contribute to autism. If those variables are associated with acetaminophen use, they could have created the appearance of a relationship that may not exist in studies that failed to properly control for them.
“In the case of acetaminophen, pregnant women take acetaminophen for a reason. They take it because they have a fever, or they have an infection or they are in pain, and these themselves are risk factors — potential risk factors — for autism,” Wang said. “They may be correlated with other causes that we can’t see.”
—Staff writer Abigail S. Gerstein can be reached at abigail.gerstein@thecrimson.com. Follow her on X @abbysgerstein.
—Staff writer Ella F. Niederhelman can be reached at ella.niederhelman@thecrimson.com. Follow her on X @eniederhelman.
