Previous studies examining reproductive parameters in men with galactosemia have inconsistently demonstrated abnormalities. We hypothesized that men with galactosemia may demonstrate evidence of reproductive dysfunction. Pubertal history, physical examination, hormone levels and semen analyses were examined in 26 males with galactosemia and compared to those in 46 controls. The prevalence of cryptorchidism was higher in men with galactosemia than in the general population [11.6 % vs. 1.0 % (95%CI: 0.75-1.26; p <0.001)]. Testosterone (461 +/- 125 vs. 532 +/- 133 ng%; p = 0.04), inhibin B (144 +/- 66 vs. 183 +/- 52 pg/mL; p = 0.002) and sperm concentration (46 +/- 36 vs. 112 +/- 75 x 10(6) spermatozoa/mL; p = 0.01) were lower and SHBG was higher (40.7 +/- 21.5 vs 26.7 +/- 14.6; p = 0.002) in men with galactosemia compared to controls. Semen volume was below normal in seven out of 12 men with galactosemia. Men with galactosemia have a higher than expected prevalence of cryptorchidism and low semen volumes. The subtle decrease in testosterone and inhibin B levels and sperm count may indicate mild defects in Sertoli and Leydig cell function, but does not point towards severe infertility causing reproductive impairment. Follow-up studies are needed to further determine the clinical consequences of these abnormalities.