What Are Sperm Telling Us?
Something alarming is happening between our legs.
Sperm counts have been dropping; infant boys are developing more genital abnormalities; more girls are experiencing early puberty; and adult women appear to be suffering declining egg quality and more miscarriages.
It’s not just humans. Scientists report genital anomalies in a range of species, including unusually small penises in alligators, otters and minks. In some areas, significant numbers of fish, frogs and turtles have exhibited both male and female organs.
Four years ago, a leading scholar of reproductive health, Shanna H. Swan, calculated that from 1973 to 2011, the sperm count of average men in Western countries had fallen by 59 percent. Inevitably, there were headlines about “Spermageddon” and the risk that humans would disappear, but then we moved on to chase other shiny objects.
四年前，生殖健康领域著名学者莎娜·H·斯旺(Shanna H. Swan)计算出，从1973年到2011年，西方国家男性的平均精子数量下降了59%。不可避免地，新闻头条中出现了“精子末日”和人类可能消失的风险，但随后我们就跑去追逐其他引人瞩目的话题。
Now Swan, an epidemiologist at Mount Sinai Medical Center in New York, has written a book, “Count Down,” that will be published on Tuesday and sounds a warning bell. Her subtitle is blunt: “How our modern world is threatening sperm counts, altering male and female reproductive development, and imperiling the future of the human race.”
现于纽约西奈山医学中心(Mount Sinai Medical Center)担任流行病学家的斯旺周二出版的新书《倒计时》(Count Down) 敲响了警钟。书的副标题很直白——“我们的现代世界如何威胁精子数量，改变男性和女性的生殖发育，并危及人类的未来”。
Swan and other experts say the problem is a class of chemicals called endocrine disruptors, which mimic the body’s hormones and thus fool our cells. This is a particular problem for fetuses as they sexually differentiate early in pregnancy. Endocrine disruptors can wreak reproductive havoc.
These endocrine disruptors are everywhere: plastics, shampoos, cosmetics, cushions, pesticides, canned foods and A.T.M. receipts. They often aren’t on labels and can be difficult to avoid.
“In some ways, the sperm-count decline is akin to where global warming was 40 years ago,” Swan writes. “The climate crisis has been accepted — at least by most people — as a real threat. My hope is that the same will happen with the reproductive turmoil that’s upon us.”
Chemical companies are as reckless as tobacco companies were a generation ago, or as opioid manufacturers were a decade ago. They lobby against even safety testing of endocrine disruptors, so that we have little idea if products we use each day are damaging our bodies or our children. We’re all guinea pigs.
Aside from the decline in sperm counts, growing numbers of sperm appear defective — there’s a boom in two-headed sperm — while others loll aimlessly in circles, rather than furiously swimming in pursuit of an egg. And infants who have had greater exposures to a kind of endocrine disruptor called phthalates have smaller penises, Swan found.
Uncertainty remains, research sometimes conflicts and biological pathways aren’t always clear. There are competing theories about whether the sperm count decline is real and what might cause it and about why girls appear to be reaching puberty earlier, and it’s sometimes unclear whether an increase in male genital abnormalities reflects actual rising numbers or just better reporting.
Still, the Endocrine Society, the Pediatric Endocrine Society, the President’s Cancer Panel and the World Health Organization have all warned about endocrine disruptors, and Europe and Canada have moved to regulate them. But in the United States, Congress and the Trump administration seemed to listen more to industry lobbyists than to independent scientists.
尽管如此，内分泌学会(Endocrine Society)、儿科内分泌学会(Pediatric Endocrine Society)、总统癌症小组(President’s Cancer Panel)以及世界卫生组织(World Health Organization)都对内分泌干扰素发出了警告，欧洲和加拿大已采取行动，对其进行监管。但在美国，国会和特朗普政府似乎更愿意听取行业游说者的意见，而不是独立科学家的意见。
Patricia Ann Hunt, a reproductive geneticist at Washington State University, has conducted experiments on mice showing that the impact of endocrine disruptors is cumulative, generation after generation. When infant mice were exposed for just a few days to endocrine disrupting chemicals, their testes as adults produced fewer sperm, and this incapacity was transmitted to their offspring. While findings from animal studies can’t necessarily be extended to humans, after three generations of these exposures, one-fifth of the male mice were infertile.
华盛顿州立大学(Washington State University)生殖遗传学家帕特里夏·安·亨特(Patricia Ann Hunt)在小鼠身上进行的实验表明，内分泌干扰素的影响是不断累积的，一代又一代。幼鼠接触内分泌干扰化学物质数天，成年后睾丸产生的精子数量更少，这种能力的丧失会传递给后代。虽然动物研究的结果不一定适用于人类，但是经过三代的接触，五分之一的雄性小鼠都无法生育。
“I find this particularly troubling,” Professor Hunt told me. “From the standpoint of human exposures, you could argue we are hitting the third generation just about now.”
What if anything does all this mean for the future of humanity?
“I do not see humans becoming extinct, but I do see family lines ending for a subset of people who are infertile,” Andrea Gore, a professor of neuroendocrinology at the University of Texas at Austin, told me. “People with impaired sperm or egg quality cannot exercise their right to choose to have a child. That may not devastate our species, but it is certainly devastating to these infertile couples.”
“我不认为人类会灭绝，但我确实认为，少数不育者的家族遗传会告终，”得克萨斯大学奥斯汀分校(University of Texas at Austin)神经内分泌学教授安德里亚·戈尔(Andrea Gore)告诉我。“精子或卵子质量受损的人无法行使选择生孩子的权利。这可能不会摧毁我们这个物种，但对这些无法生育的夫妇无疑是毁灭性的。”
More research is necessary, and government regulation and corporate responsibility are crucial to manage risks, but Swan offers practical suggestions for daily life for those with the resources. Store food in glass containers, not plastic. Above all, don’t microwave foods in plastic or with plastic wrap on top. Avoid pesticides. Buy organic produce if possible. Avoid tobacco or marijuana. Use a cotton or linen shower curtain, not one made of vinyl. Don’t use air fresheners. Prevent dust buildup. Vet consumer products you use with an online guide like that of the Environmental Working Group.
有必要进行更多的研究，政府监管和企业责任对管理风险至关重要，但斯旺为有条件的人提供了日常生活的实用建议。使用玻璃容器而不是塑料容器储存食物。最重要的是，微波炉加热食品时不要使用塑料容器或者覆盖保鲜膜。避免农药。如果可能的话，购买有机农产品。避免烟草或大麻。使用棉质或亚麻浴帘，而不是乙烯基浴帘。不要使用空气清新剂。防止灰尘积聚。使用环境工作组(Environmental Working Group)等机构的在线指南来审核你使用的消费品。
Many issues in headlines today won’t much matter in a decade, let alone in a century. Climate change is one exception, and another may be the risks to our capacity to reproduce.
The epitome of a “low blow” is a kick to the crotch. And that, friends, may be what we as a species are doing to ourselves.