One example of the consequences of the exposure of developing animals, including humans, to hormonally active agents is the case of the drug diethylstilbestrol (DES), a nonsteroidal estrogen and not an environmental pollutant. Prior to its ban in the early 1970s, doctors prescribed DES to as many as five million pregnant women to block spontaneous abortion, an off-label use of this medication prior to 1947. It was discovered after the children went through puberty that DES affected the development of the reproductive system and caused vaginal cancer. The relevance of the DES saga to the risks of exposure to endocrine disruptors is questionable, as the doses involved are much higher in these individuals than in those due to environmental exposures.