Male fecundity may be largely determined through fetal programming and therefore potentially be sensitive to exposure to maternal alcohol intake during pregnancy. We investigated whether maternal alcohol intake in early pregnancy was associated with biomarkers of fecundity in adult sons. In total, 1058 sons from the Fetal Programming of Semen Quality (FEPOS) cohort nested in the Danish National Birth Cohort (DNBC) provided blood and semen samples at around 19 years of age. Information on maternal weekly average alcohol intake (0 drinks [ref], >0-1 drinks, >1-3 drinks, >3 drinks) and binge drinking episodes (intake of ≥5 drinks on one occasion: (0 [ref], 1-2, ≥3 episodes)) was self-reported at around gestational week 17. Outcomes included semen characteristics, testes volume and reproductive hormones. We found some small tendencies towards lower semen characteristics and an altered hormone level profile in sons of mother who had an intake of > 3 drinks/week in early pregnancy and sons of mother who had ≥ 3 episodes of binge drinking in pregnancy. However, the effect estimates were overall small and inconsistent and with no indication of a dose dependent association. Due to the limited number of mothers with a high weekly alcohol intake, we cannot exclude whether prenatal exposure to higher doses than 4.5 drinks/week of alcohol in early pregnancy might have a detrimental effect on the biomarkers of fecundity in adult sons..