OBJECTIVE To investigate the effects of hypoxia during the prenatal period and its later repercussions on sexual behavior and the sex hormone secretion of male rats. METHODS Experimental animals were divided into three groups randomly: control group, which was kept at normal atmospheric pressure, and two stress groups exposed to a simulated altitude equivalent to 3000 m and 5000 m, respectively. Stress groups were exposed to hypoxic circumstance at their final week of gestation in animal decompression chamber. RESULTS Adulthood, males exposed to hypoxic stress during the prenatal period were able to mate with normal females, but these treated males exhibited decreased male sexual behavior. Decreased anogenital distances were observed in male offspring, and presented reductions of plasma testosterone levels, increase of plasma corticosterone levels, but no notable alteration in the organ index. CONCLUSIONS These results indicate that exposure to hypoxia in the later stages of pregnancy may have a long-term effect on the fertility and sexual behavior of male offspring.