Quote:The federal government’s new warning that taking Tylenol during pregnancy may lead to autism should prompt the revival of lawsuits from mothers who allege Tylenol caused their children’s autism or attention-deficit/hyperactivity disorder (ADHD), attorneys for the families said in a new filing.
Federal officials on Sept. 22 moved to update labeling for Tylenol and other drugs containing acetaminophen, which are used for pain and fever relief. Regulators said that “the use of acetaminophen by pregnant women may be associated with an increased risk of ... autism and ADHD in children.”
During a press conference announcing the moves, Food and Drug Commissioner Dr. Marty Makary quoted Dr. Andrea Baccarelli, a dean at the Harvard School of Public Health, who said in his expert opinion in the legal case that “there is a causal relationship” between in utero exposure to acetaminophen and neurodevelopmental disorders such as autism.
“Expert opinion that is sound enough to persuade every Senate-confirmed federal scientist easily clears Rule 702(d)’s bar,” the attorneys said in the filing on Wednesday, referring to a rule governing the use of expert witnesses in litigation.
“Reasonable scientists can continue to debate Dr. Baccarelli’s conclusions. But affirming a decision characterizing his approach as ‘junk science’ would pose grave separation of powers concerns,” the attorneys said. “The executive branch safeguards public health from dangerous pharmaceutical interventions. A decision holding that a jury may not hear the same expert evidence that the executive branch credited will badly damage the public trust required for the executive to take care that the public-health laws are faithfully executed.”
The lawsuits in question alleged that retailers and Kenvue, which makes Tylenol, failed to warn people that drugs containing acetaminophen could cause autism or ADHD. U.S. District Judge Denise Cote ruled in 2023 that Baccarelli and other experts offered by plaintiffs cherry-picked and misrepresented the results of studies. She later dismissed the cases.

In their appeal, lawyers for the families said that “a wealth of scientific evidence suggests that prenatal exposure to acetaminophen (APAP) causes autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD).” They said the judge should not have dismissed the cases or rejected their expert witnesses.
Oral arguments in the appeal are set for Oct. 6 in New York City before the U.S. Court of Appeals for the Second Circuit.
Attorneys for Kenvue told the appeals court in response to the new filing that the federal government’s actions do not establish a causal association, noting that the FDA said in its letter to doctors that “while an association between acetaminophen and autism has been described in many studies, a causal relationship has not been established and there are contrary studies in the scientific literature.”
“The statements of the government and Dr. Baccarelli himself confirm that the existing evidence does not support a causal relationship, and that the district court was thus correct to conclude it is not ’reliable to draw a causal inference from the associations that researchers have observed,'” the lawyers said. They said the appeals court should uphold Cote’s rulings.