❓WHAT HAPPENED: The use of Tylenol, also known by its generic names paracetamol and acetaminophen (APAP), by pregnant women has been linked to “developmental alterations in both the reproductive tract and the brain” of unborn babies—especially boys.
👤WHO WAS INVOLVED: The Society for Reproduction and Fertility’s journal Reproduction; researchers hailing from Denmark, Brazil, France, Sweden, and the United States; the Trump administration; and pregnant women.
📍WHEN & WHERE: The study was conducted in 2017, with the Trump administration issuing new guidance for pregnant women on Tylenol use in September 2025.
💬KEY QUOTE: “Together, these data suggest that prenatal exposure to APAP may impair male sexual behaviour in adulthood by disrupting the sexual neurobehavioral programming. These findings add to the growing body of evidence suggesting the need to limit the widespread exposure and use of APAP by pregnant women,” the 2017 study researchers wrote.
🎯IMPACT: The 2017 study bolsters new guidance issued by the Trump administration warning against the use of Tylenol by pregnant women due to potential links to the development of autism in children.
The use of Tylenol, also known by its generic names paracetamol and acetaminophen (APAP), by pregnant women has been linked to “developmental alterations in both the reproductive tract and the brain” of unborn babies, especially boys. A 2017 study, published in the Society for Reproduction and Fertility’s journal Reproduction, found that paracetamol/acetaminophen exposure in fetal male mammals has significant impacts on both physical and neurological sexual development that could still be observed in later adulthood.
“Through intrauterine exposure experiments in C57BL/6 mice, we found that exposure to APAP decreased neuronal number in the sexually dimorphic nucleus (SDN) of the preoptic area (POA) in the anterior hypothalamus of male adult offspring,” the 2017 study states. “Likewise, exposure to the environmental pollutant and precursor of APAP, aniline, resulted in a similar reduction. Decrease in neuronal number in the SDN-POA is associated with reductions in male sexual behaviour.”
The researchers—hailing from Denmark, Brazil, France, Sweden, and the United States—observed that fetal exposure to APAP altered critical mating behaviors in adult male mice, including territorial marking through urination and decreased aggressiveness toward the presence of other male mice. Concerningly, the study also found “exposed males had reduced intromissions and ejaculations during mating with females in oestrus.”
“Together, these data suggest that prenatal exposure to APAP may impair male sexual behaviour in adulthood by disrupting the sexual neurobehavioral programming,” the researchers contend, adding: “These findings add to the growing body of evidence suggesting the need to limit the widespread exposure and use of APAP by pregnant women.”
The 2017 study bolsters new guidance issued by the Trump administration, warning against the use of Tylenol by pregnant women due to potential links to the development of autism in children. The National Pulse previously reported that a now-defunct social media account for Tylenol warned in 2017 and 2019 that pregnant women should avoid its use.
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