Genital tract examinations and zona-free hamster egg penetration tests from men exposed in utero to diethylstilbestrol.

Because most men with prenatal exposure to diethylstilbestrol (DES) are still young and have not attempted to father children, its reproductive effects are uncertain. In a previous pilot study, we had noted an association between in utero DES exposure and reduced penetration of zona-free hamster eggs by sperm. To test these findings in a controlled manner, we performed physical examinations on 51 men with in utero DES exposure and 29 unexposed men and evaluated the penetration of zona-free hamster eggs by their sperm. Epididymal cysts or abnormalities of the prostate, testicle, or penile meatus were present in 37% of men with in utero DES exposure, versus 4% of nonexposed men (P less than 0.001). The mean proportions of penetrated eggs were 25% after in utero DES exposure and 29% in the nonexposed group (P greater than 0.57). The genital abnormalities related to DES exposure were not related to reduced egg penetration. We conclude that in utero exposure to DES is not related to a significant change in the penetration of zona-free hamster eggs by sperm.