Workplace exposure to bisphenol-A (BPA)—a potential human endocrine disruptor widely used in plastic and resin consumer products—is associated with impaired male sexual function. So says a Sino–American group of researchers, who investigated the effects of occupational exposure to BPA among male factory workers in China. “Defenders of BPA safety have been asking for evidence of an adverse effect of BPA in human studies,” says De-Kun Li, lead author on the study. “Now, our findings start to demonstrate adverse effects of BPA on male sexual function.”

The study included 164 men who were exposed to high levels of BPA in the workplace and 386 men without exposure. Workers exposed to BPA had a significantly higher likelihood of reduced sexual desire (odds ratio [OR] 3.9, 95% CI 1.8–8.6), erectile dysfunction (OR 4.5, 95% CI 2.1–9.8), ejaculatory dysfunction (OR 7.1, 95% CI 2.9–17.6), and reduced satisfaction with their sex lives (OR 3.9, 95% CI 2.3–6.6; all measured using the International Index of Erectile Function and the Brief Male Sexual Function Inventory). The researchers also identified a dose–response relationship between BPA exposure and risk of sexual dysfunction. Significant impairment of sexual function was apparent among men whose duration of exposure to BPA was as short as 1 year or less.

“In animals, BPA adversely affects male sexual function through its estrogenic and antiandrogenic effects,” says Li. “Until our publication, however, no human study has shown the effect of BPA on male sexual function.”

If replicated, these results might have significant public health implications, given the widespread occupational and environmental human exposure to BPA. Whether the observed effect is unique to highly exposed workers, or is seen at lower, environmental, BPA doses, remains to be determined.