U.S. — A peer-reviewed study published in the journal Scientific Reports in September 2025 indicated that the linguistic framing of public health claims influences public perception of a link between Tylenol use during pregnancy and autism risk. The study found that phrasing such as 'is linked with' was interpreted as less causal than 'causes'.

Researchers conducted an experiment with 1,957 individuals recruited from CloudResearch’s Connect platform to analyze how people interpret different wordings of public-health claims. The study compared three phrasings: 'causes', 'increases the risk of', and 'is linked with'. Participants were less likely to strongly support the Tylenol-autism relationship when the 'causes' phrasing was used compared to 'increases the risk of'.

In an exploratory ordinal analysis, the odds of stronger endorsement were approximately 22% lower for the 'causes' phrasing when compared to other phrasings. The phrases 'is linked with' and 'increases the risk of' were endorsed at similar rates by study participants. Study participants with a college degree endorsed the phrase 'is linked with' more strongly than the phrase 'causes'.

Higher education correlated with greater skepticism toward the Tylenol-autism claim overall. Participants with a four-year college degree exhibited 34% lower odds of endorsing the claim than individuals with lower educational attainment. The study found that Republicans, Democrats, and Independents differed in their overall likelihood of endorsing the claim but responded similarly across the three phrasings.

Republicans had about 9.8 times higher odds of endorsing the statement compared with Democrats, while Independents had 3.25 times the odds of endorsing the statement compared with Democrats. The study did not assess the biological relationship between acetaminophen and autism. The study title is 'Endorsement of increased-risk claims about Tylenol and autism may not reflect causal beliefs'.

Many respondents in a KFF poll said it was probably or definitely true that Tylenol use during pregnancy increases autism risk; however, that poll did not directly ask whether respondents believed Tylenol causes autism. Nearly 90% of the Scientific Reports study participants were aware of the topic of Tylenol use during pregnancy and autism.

Why It Matters

This study highlights the impact of language on public understanding of scientific information, particularly concerning health-related issues. The findings suggest that the choice of words in communicating scientific claims can influence public perception of causality, with implications for public health messaging and how information about potential risks is conveyed to a broad audience, including those with varying educational backgrounds.