Diethylstilbestrol: The earliest synthetic (man-made) form of the hormone estrogen.

Diethylstilbestrol (DES) was once widely prescribed to prevent miscarriages and premature births. Its usage was standard practice in the 1950s and 1960s. Millions of women received the drug.

Girls whose mothers were given DES during pregnancy ("DES daughters") were discovered to be at increased risk for being born with malformations of the reproductive organs and to face elevated rates of infertility and miscarriages themselves.

DES daughters were also found to be at increased risk for cancer of the cervix and vagina, specifically for developing clear-cell adenocarcinoma of the vagina and cervix, a relatively uncommon type of cancer, at an early age. In 2000, DES daughters were reported to be 3-5 times more likely to have the more common forms of cervical cancer than women whose mothers did not take DES.

DES sons are predisposed to testicular abnormalities, such as abnormally small testes) and failure of the testes to descend into the scrotum, which increases the risk of testicular cancer. All women and men who believe they may have been exposed to DES before birth should inform their doctor of their exposure so that they may be appropriately examined and monitored.

DES is still available for prescription in the US. According to the package insert, DES "is indicated for the treatment of" (and we quote):

1. "Breast cancer (palliation only) in appropriately selected women and men with metastatic disease" and
2. "Prostatic cancer -- palliative therapy of advanced disease."