Long-term effects on male reproductive organs of prenatal exposure to ethinyl estradiol.

The effects of oral contraceptives on human offspring have not been established. This study shows the long-term effects of prenatal exposure to ethinyl estradiol, a common estrogenic component of oral contraceptives, on the testes and epididymides of aged mice. Five (83%) of the six aged male mice examined showed atrophy of seminiferous tubules, four (67%) had Leydig's cell hyperplasia, and one (17%) had precancerous changes in the epididymis. These phenomena may be results of decreases in testosterone content and its drastic conversion into estradiol-17 beta in the fetal testes at critical periods induced by ethinyl estradiol.