"A direct link between the plastics component bisphenol A, or BPA, and disrupted sperm production has been discovered by researchers. They say the chemical disrupts the delicate DNA interactions needed to create sperm. This work may have unearthed the physiological mechanism that could account for decreased sperm counts seen in several human studies."
In addition to seeing BPA effects, Hunt and her colleagues saw an even larger effect on sperm by estradiol, the birth control hormone that passes untreated through sewage plants.
Hunt has a long history of working with BPA, which is often found in plastic bottles, the linings of food and beverage cans, and thermal receipts. Much of her work has documented its effect on female reproduction, from mice to monkeys.
Declining sperm counts have been a subject of concern and conjecture since the early 1990s, when Danish researchers reported "a genuine decline in semen quality over the past 50 years," with possible implications for male fertility. Sperm count studies have often been criticized for being small, having biased populations or questionable statistical methods, but reproductive biologists continue to see data suggesting that endocrine disruptors like BPA, plastic-softening phthalates and estradiol are impairing reproduction. In a 2013 study cited by Hunt and her colleagues, French researchers looked at the partners of more than 26,000 infertile women and saw their semen concentration drop nearly 2 percent a year for 17 years.