We trust our doctors to prescribe us medication that will make us better off, rather than worse off. However, sometimes drugs that are believed to be safe at the time are in fact dangerous, and the results can be devastating.

Forty years ago, research revealed that the drug DES, commonly prescribed to prevent pregnancy complications in women during the mid-20th century, caused various birth injuries. This week, Reuters reported that a recent study found that the drug may still cause these harmful effects in third-generation children.

Four decades ago it was determined that girls exposed to DES, or diethylstilbestrol, in the womb were more likely to develop cancer in the vagina. Years later, more research revealed that girls whose mothers took DES during their pregnancies also had a higher rate of birth defects and fertility problems.

Now, Reuters has reported that French researchers found that the third generation grandsons of women who took DES while pregnant have a greater chance of having deformations in the opening of the penis. One penal deformation found in the boys is hypospadias, which results in the urethra to end somewhere along the penis or close to the scrotum, rather than at the tip of the penis.

The hypospadias deformation is believed to be found in 4 out of 1,000 boys born, and while some studies show a link between DES and hypospadias, the Centers for Disease Control and Prevention said that it is not clear that DES exposure causes the problem, Reuters reported.

However, the recent French study looked at the presence of hypospadias among the grandsons of women who took DES and found that 8 out of every 100 boys who were exposed to DES had the defect. What's more, the only grandsons to have the deformity were the sons of daughters who had been exposed to DES while in their mothers' wombs.

Researchers are perplexed by the results, guessing that the eggs of a woman who had been exposed to DES in the womb could have been damaged, thus causing the defect in her son. Another guess is that the drug affected the genes of the women who had been exposed, which would pass down to future generations.

On the other hand, Reuters pointed out that some believe there could be no link at all, and the study was flawed. Regardless, dangerous drugs can cause devastating results.

Source: Reuters, "Grandsons may be affected by old pregnancy drug," 4/20/11.