From the 1940s to the 1970s, diethylstilbestrol (DES) was used in some pregnant women to prevent miscarriage. Many sons and daughters of women who used DES have developed abnormalities of the reproductive organs.
A woman who was exposed to DES in her mother's uterus may have abnormalities in her cervix, uterus, or vagina. A man who was exposed to DES in his mother's uterus may have abnormalities in the size of his penis, the opening of the urethra, and the testicles.
Exposure to DES in the mother's uterus causes these problems in both men and women.