Diethylstilbestrol (DES), which was the first synthetic estrogen ever developed, is today occasionally utilized in hormone replacement therapy, but was more often prescribed to pregnant women from 1938 to 1971. The drug was supposed to prevent miscarriages and aid in the development of strong, healthy children, although studies indicated its ineffectiveness for such purposes by the mid-1950s. Some early research also linked the drug to cancer in laboratory animals, but despite such evidence, DES continued to be marketed to pregnant females for many years. It was not until the early 1970s, when it was demonstrated statistically that the female offspring of women taking DES exhibited abnormally high rates of an otherwise rare form of cancer that the Food and Drug Administration finally issued a notice to the medical community to stop prescribing the drug to pregnant women. Since that time, research has revealed that the sons of DES daughters are also at higher risk for certain health problems, including genital malformations and epididymal cysts.