The finding that even low doses of acetaminophen (indicated by the number of weeks of drug exposure) can affect behaviour 7 years later is alarming because acetaminophen (paracetamol) is the most commonly used antenatal drug [5]. If supported, under- standing the biological mechanism underlying the acetaminophen- behaviour link would likely take precedent in tandem with efforts to inform the general public of the newly identified risks of this commonly used over-the-counter drug. The finding is also noteworthy because of the many strengths of the above study. Firstly, the sample consisted of a large cohort of mothers