Diethylstilbestrol, Diethylstilbestrol

Diethylstilbestrol can also cause feminisation of the male foetus, as DES undergoes metabolic epoxidation, and the epoxide product has affinity towards the estrogen receptors. In some cases there are sons with only one testis or both abdominal. In 2002, a study indicated that maternal usage of DES resulted in a 20-fold increase in prevalence of hypospadias in their sons although a followup study showed the risk, though present, to be much lesser.

Source: Wikipedia > Diethylstilbestrol