Wreaking Reproductive Havoc One Chemical at a Time

PLoS Biology, 2016


In the 1930s, biochemist Edward Charles Dodds hoped to find synthetic estrogens that could treat gynecological ailments caused by hormone deficiencies. In 1936, Dodds identified one candidate that stimulated the female reproductive system in rats whose ovaries had been removed. But the estrogenic activity of the compound, bisphenol A, paled next to the much stronger estrogen he would soon develop himself: diethylstilbestrol (DES).

Dodds had noticed estrogen’s similarity to cancer-causing substances in early studies, but assumed that any drugs would be used only as short-term therapies, so the cancer risk would be small. He never expected DES or any other estrogens to be given to healthy women. Yet some 4 million expectant mothers received DES to prevent miscarriage before physicians realized they’d made a terrible mistake. DES greatly increased the risk of rare vaginal and cervical cancers in exposed daughters. Sons had a higher risk of testicular growths. …

… The negative effects of estrogenic chemicals we encounter every day include an expanding list of changes to intricately choreographed programs that shape our capacity to grow and thrive. The complexity of these developmental dances, which overlap in space and time in the growing embryo, has often made it difficult for researchers to pin down exactly how these compounds cause harm. And that’s allowed chemical companies to continue arguing that there’s no evidence their products pose a threat to public health.

Yet Dodds warned over 50 years ago that continuous exposure to estrogens could pose serious health risks. He was worried about the long-term use of oral contraceptives, which were far stronger back then. Imagine what he would think of the constant stream of synthetic estrogens we’re exposed to today.


  • Wreaking Reproductive Havoc One Chemical at a Time, PLoS Biology, NCBI PubMed PMC4996459, 2016 Oct.
  • Featured image Markus M.

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