53 women around the country are suing drug companies on a claim that a drug that their mothers took to prevent miscarriages caused them to develop breast cancer. Scientifically, of course, the link is very hard (likely impossible) to prove, but the drug has been linked by the U.S. Food and Drug Administration to other cancers, causing the drug's discontinuation in 1971.

The drug, called DES, was a synthetic estrogen developed in the 1930s and prescribed to women in the U.S. and Europe from 1938 to 1971. It was developed and believed to lower the risk of miscarriage during pregnancy.

In the 1960s, it was suspected of playing a role in increasing or causing a rare vaginal cancer. An investigation and study by the FDA found a plausible link and so the agency ordered the drug be removed from shelves and discontinued.

Since then, thousands of lawsuits in the U.S. have been filed alleging links between DES and cervical and vaginal cancers in women who took the drug as well as infertility problems for their daughters.

The current suit is the first time DES has been accused of causing breast cancer.

Source: http://www.breastcancer.co/news/drugs-and-medication/old-drug-blamed-for-breast-cancer-in-women-whose-mothers-took-it-during