Human fertility rates are plummeting amid a tidal wave of endocrine-disrupting chemicals.
Plastic is such a ubiquitous part of modern life that it’s hard to imagine a world without it. But in the grand scheme of things, plastics are still a new invention.
As noted by Pete Myers, the chair, founder, and chief scientist of Environmental Health Sciences, there’s a lot we don’t know about plastics and health—but then, there’s a lot that we do.
Particularly when it comes to the chemicals in plastics, much is known about the risks they pose to human health, including to future generations through intergenerational endocrine disruption.
“It’s enough to give me great pause,” says Myers.
Endocrine disruptors—which are widespread in plastic products and similar in structure to natural sex hormones such as estrogen—interfere with normal hormone function, and more. According to Myers and other researchers, these chemicals jeopardize the reproductive health—and continuation of—the entire human race. 
“Your hormones have been hijacked. Your body’s astonishing, finely calibrated signal system—a system that controls everything from your weight to your fertility to your mood—has been scrambled by loosely regulated chemicals manufacturers use in a myriad of ways including in consumer products,” says Myers.
These hijackers—known to scientists as ‘endocrine-disrupting chemicals’—are threatening our existence as a species. Driving this problem are chemical companies focused only on cheap plastics and regulators unwilling to do anything about it.”
Male Fertility Is on the Decline, Could Reach Zero by 2045
Myers highlights the book “Count Down,” written by Shanna Swan, a reproductive epidemiologist at Mount Sinai’s Icahn School of Medicine. It’s based on a 2017 study she co-wrote, which found sperm counts dropped by 59.3 percent from 1973 to 2011.
The most significant declines were found in samples from men in North America, Europe, Australia and New Zealand, where many had sperm concentrations below 40 million/ml, which is considered the cutoff point at which a man will have trouble fertilizing an egg. Overall, men in these countries had a 52.4 percent decline in sperm concentration and a 59.3 percent decline in total sperm count (sperm concentration multiplied by the total volume of an ejaculate).
The book expands on what Swan describes as an impending fertility crisis; along with the dropping sperm counts, changes in sexual development pose a threat to human survival.
“The current state of reproductive affairs can’t continue much longer without threatening human survival,” warns Swan. In fact, she estimates that if current projections continue, sperm counts could reach zero in 2045.
Global fertility rates are also falling, reaching 2.4 births per woman in 2018, down from 5.06 in 1964. Fertility rates in about 50 percent of countries worldwide are at 2.1, which is below population replacement level.
This cataclysmic drop in fertility rates makes human beings an endangered species, according to Swan and the generally accepted criteria for defining an endangered species. Within a generation, we could see a staggering decline in human reproduction. While there are numerous factors involved—including contraception and costs of raising children—biological reasons, such as declining sperm counts, increasing miscarriage rates, and genital abnormalities, are also driving down birth and fertility rates.
Endocrine-disrupting “everywhere chemicals” are a key culprit, she writes: “Chemicals in our environment and unhealthy lifestyle practices in our modern world are disrupting our hormonal balance, causing various degrees of reproductive havoc.”
Has the ‘Count Down’ to Infertility Begun?
“Count Down” brings some little-known findings into the spotlight, like the fact that a significant part of the global population may not be able to reproduce without technological assistance come 2050. Men today have about half the number of sperm compared to their grandfathers.
There appears to be a synergy occurring as well, which the book dubs “the 1 percent effect.” Sperm count, testosterone, and fertility are all dropping at about 1 percent a year while testicular cancer and miscarriage are rising at about the same rate.
Studies continue to link endocrine-disrupting chemical (EDC) exposure to reproductive health problems. One review of 35 studies looked at one common EDC—Bisphenol A.
”According to our findings, BPA has a direct negative impact on maternal, fetal, and neonatal outcomes, including birthweight, rates of preterm birth, developmental defects, and recurrent miscarriage,” wrote researchers in their 2017 review published in The Journal of Maternal-Fetal & Neonatal Medicine.
Another EDC used for making plastics more flexible is known as di-(2-ethylhexyl)phthalate (DEHP), a phthalate plasticizer.
“Clinical and experimental studies have indicated that exposure to DEHP is associated with developmental abnormalities of the reproductive system particularly of male neonates, endometriosis and miscarriage in women, low sperm counts and lower sperm motility and DNA integrity in men, and placental problems with higher rates of low birth weight, premature birth, and fetal loss in laboratory animals,” warned researchers in a 2016 study published in Journal of applied toxicology.
Chemical exposure during pregnancy has been found to affect both masculinization and long-term fertility in males. In the wild, fish, frogs and reptiles are also increasingly being born with both ovaries and testes.
Environmental Chemicals Causing Fertility Declines
A number of chemicals are wreaking havoc with human fertility. EDCs interfere with endogenous hormones, and it’s been found that some effects of exposure persist in future generations, even among males that weren’t directly exposed.
Research published in PLOS Genetics, for instance, found that exposing male mice to ethinyl estradiol, a synthetic sex hormone found in birth control pills, causes developmental problems in the reproductive tract, thereby lowering sperm counts (men may be exposed to birth control pills through contaminated water and other sources).
This study also revealed the generational effects of EDCs. Environmental Health News reported:
“They observed adverse effects starting in the first generation of mouse lineages where each generation was exposed for a brief period shortly after birth. The impacts worsened in the second generation compared to the first, and by the third generation the scientists were finding animals that could not produce sperm at all.”
“This latter condition was not seen in the first two generations exposed. Details of the experimental results actually suggested that multiple generations of exposure may have increased male sensitivity to the chemical.”
Other research adds further evidence that environmental chemicals are involved in fertility declines. A study published in Scientific Reports in 2016 found that dogs living in human households suffered similar declines in sperm quality to humans, with sperm motility declining by 30 percent over a 26-year period.
In the canine study, the researchers linked certain environmental chemicals to sperm problems and suggested they could also be responsible for the sperm quality declines in humans—a notion supported by a 2019 follow-up study also published in Scientific Reports.
Researchers from the University of Nottingham used sperm samples from 11 men and nine dogs from the same U.K. region. They exposed the sperm to doses of two types of environmental chemicals, diethylhexyl phthalate (DEHP) and polychlorinated biphenyl 153 (PCB153), currently found in the environment. The result was reduced sperm motility and increased DNA fragmentation.
The researchers believe dogs may act as a “sentinel” for declines in male fertility and that man-made chemicals used widely in home and work environments are the likely culprit. The previous 2016 study even detected such chemicals in dog sperm and some dog food.
Top Sources of Endocrine Disruptors
The Environmental Working Group (EWG) named the following 12 chemicals in their “dirty dozen” list of EDCs: