New research is revealing a puzzling change in men that could contribute to fertility problems in America's families — and some of the conveniences of modern life could be to blame.
The change is in the sperm of young men. Studies are finding that men's sperm counts are down, and up to 90 percent of sperm examined under a microscope are deformed or misshapen. And it's not just happening in America: At fertility clinics in China, only 18 percent of potential sperm donors qualified in 2015, compared to 56 percent in 2001, columnist Nicholas Kristof wrote recently in The New York Times.
"Even when properly shaped, today's sperm are often pathetic swimmers, veering like drunks or paddling crazily in circles," Kristof wrote. The change is so pronounced, he said, that some scientists have been warning for more than two decades that we're headed toward a reproductive crisis.
"Not everyone who wants to reproduce will be able to. And the costs of male disorders to quality of life, and the economic burden to society, are inestimable," Andrea Gore, a professor of pharmacology at the University of Texas at Austin and editor of the journal Endocrinology, told Kristof.
Gore's work focuses on endocrine-disrupting chemicals, or EDCs, which many researchers believe may be responsible for disrupting reproductive function in both men and women, contributing to breast cancer and early puberty, and causing neurodevelopmental delays in children, among other ill effects.
Chronic exposure to manmade chemicals — including those in pesticides, personal care products and flame retardants — is to blame, the researchers believe, as well as the traces of chemicals that we ingest from the packaging of food and drinks.
The link has not been proven in humans, but in animal studies, the effects of EDCs are troubling, and there is a growing call for people to avoid chemical exposure. While there's no downside to such a precaution other than inconvenience, it's too soon to panic, and chances are your sperm (or that of your husband) is just fine, says Geoffrey Kabat, a cancer epidemiologist at Albert Einstein College of Medicine in New York City.
Sperm count and mobility vary not only by geography, but by individual, Kabat wrote in Forbes. If you're measuring yours through new technology, like smartphone app, your sperm could be sluggish because you've been sitting or eating too much.
"In addition, sperm number and quality are only weakly associated with male fertility," Kabat wrote.
So, even if both you and your spouse have been drinking out of water bottles twice a day for a decade, health experts remain divided on whether or not exposure to chemicals used to make plastic will affect your ability to conceive, or the health of your future children. But it's worth knowing what both sides are saying so you can decide what risks you are willing to take.
Twenty-five years ago, a study published in the BMJ (formerly, the British Medical Journal) concluded that sperm counts worldwide had declined 40 percent in the past 50 years and that there was a "genuine decline" in semen quality over the same period.
Twenty years later, in 2012, The Endocrine Society and IPEN, an environmental advocacy group, released a paper making the case that endocrine-disrupting chemicals are responsible for a host of reproductive issues and diseases. The lead author was Gore, the pharmacology professor quoted in Kristof's recent column in The New York Times.
The paper explained that "EDCs often disrupt endocrine systems by mimicking or blocking a natural hormone. In the case of hormone mimics, an EDC can 'trick' that hormone's receptor into thinking that the EDC is the hormone, and this can inappropriately activate the receptor and trigger processes normally activated only by a natural hormone."
Pregnant women and babies are particularly vulnerable to EDC exposure, and the chemicals can cause changes that don't emerge for decades, the paper said.
While conceding that many of the charges against EDCs are associative, there is evidence that chemicals are causing reproductive changes in wildlife, the groups noted. Alligators in Florida and frogsin Minnesota are among creatures exposed to water-borne chemicals that later exhibited "genital and reproductive malformations." But the link between EDCs and human health issues can't be proven because such testing would be unethical, the groups said.
"An additional challenge is that humans are exposed to a complex mixture of chemicals across the lifespan, making it difficult to establish if health effects result from exposure to a few problematic chemicals or a collective combination of chemicals," the paper said.
Still, the paper likens the debate over EDCs to the debate over tobacco in the latter half of the 20th century, and says that the evidence we have is strong enough that people should take steps to limit their exposure by avoiding food packaged in cans or plastic containers.
The U.S. Department of the Interior says that Minnesota's deformed frogs could have been affected by exposure to chemicals — but that an abundance of ultraviolet light and an outbreak of parasites might also be to blame.
Writing in Forbes, Kabat, the cancer epidemiologist, offered other possibilities for worldwide changes in sperm count and health.
"Advocates' narrow focus on trace chemical residues blots out consideration of the many real-world factors that have documented health effects and are likely to dwarf any effects of EDCs. These include the increasing consumption of calorie-dense foods and its attendant effects on the prevalence of obesity and diabetes, medications, endogenous hormone production, and physical activity/sedentary behavior," he wrote.
Kabat suggested that EDC research has grown into a self-supporting industry, and quoted Richard M. Sharpe of the University of Edinburgh, an expert on male reproduction, as saying, "So many people's labs, careers, and funding are dependent on the 'threat' from EDCs being real and important that they do not look in any other direction for explanations."
The National Institutes of Health addresses the subject carefully, saying chemicals "may" interfere with the body's endocrine system and "produce adverse developmental, reproductive, neurological, and immune effects in both humans and wildlife." The NIH calls for more study.
On its website, the National Institute of Environmental Health Sciences does note that EDCs "may pose the greatest risk during prenatal and early postnatal development when organ and neural systems are forming." And even if that's yet to be proven, for many families, that will be reason enough to avoid them.
We don't just ingest EDCs from food packaging; we also inhale them. They may be floating around your house, microscopic escapees from electronics, vinyl shower curtains and faux-leather furniture.
That's one reason that the Natural Resources Defense Council recommends that people dust and vacuum frequently, using a vacuum with a HEPA filter. The group also recommends that people avoid products that are scented (to include diapers and trash bags), and buy fewer products in plastic or cans. Washing your hands often also gets chemicals off your hands; just avoid antibacterial or scented soaps.
The Environmental Working Group says to shun paper receipts (coated with BPA, a chemical used in some plastics and resins), get a water filter, buy organic and eat less meat. Also, don't use non-stick pans and trays, since the chemicals on them have been found to affect hormone levels in animals.
But while you're making all these changes, know that your body is working hard at getting rid of chemicals, too.
"Since many of the EDCs have a short half-life, they can be quickly flushed out of your body once the exposure is removed," Rick Smith, co-author of "Slow Death by Rubber Duck", told Virginia Sole-Smith, writing for Parents magazine.