Concurrent alcohol exposure has been associated with reduced fecundity, but no studies have estimated the effect of prenatal alcohol exposure on male fecundity.
The aim of this study was to investigate the association between maternal alcohol consumption during pregnancy, semen quality and levels of reproductive hormones in young, adult men.
From a Danish pregnancy cohort established in 1984–1987, 347 sons were selected for a follow-up study conducted in 2005–2006. Semen and blood samples were analyzed for conventional semen characteristics and reproductive hormones, respectively, and results were related to prospectively self-reported information on maternal alcohol consumption during pregnancy.
The sperm concentration decreased with increasing prenatal alcohol exposure. The adjusted mean sperm concentration among sons of mothers drinking 
4.5 drinks per week during pregnancy was 40 (95% CI: 25–60) millions/ml. This concentration was 
32% lower compared with men exposed to > had a sperm concentration of 59 (95% CI: 44–77) millions/ml. The semen volume and the total sperm count were also associated with prenatal alcohol exposure; sons prenatally exposed to 1.0–1.5 drinks per week had the highest values. No associations were found for sperm motility, sperm morphology or any of the reproductive hormones, including testosterone.
These results indicate that prenatal exposure to alcohol may have a persisting adverse effect on Sertoli cells, and thereby sperm concentration. If these associations are causal they could explain some of the reported differences between populations and long-term changes in semen quality.
Request Reprint E-Mail: ceciraml@rm.dk
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