For the past decade, scientists have been sounding alarms about declining male fertility rates. Not only are humans being affected, but so are many animal species, especially fish. Some make fish have actually been seen to switch genders in response to pollution in their environment,
Over the past 50 years, male fertility has declined by approximately 50%. This is measured through sperm count, and sperm health and motility, all of which have declined sharply. While the effect is known, the cause of this decline is currently unknown.
There are, however, a variety of things that could be causing this problem. It may end up that it is not any one single issue, but a whole raft of them.
Most of our waterways now contain a veritable witches’ brew of chemicals, including pesticides from agricultural runoff, industrial chemicals, oil and fuel, and the varied contents of the domestic toilet, including drugs, antibiotics, antimicrobial soaps and the residue of contraceptives and hormone replacement therapy. Somewhere in this mix there is a chemical that has what are called anti-androgen properties. Anti-androgens inhibit the function of testosterone, and may have further effects on unborn embryos. The condition is called testicular dysgenesis syndrome, and can cause reproductive damage to male children, resulting in infertility, and possible testicular cancer.
Recent studies have provided a positive link between the plastic bottles used for bottled water and a class of chemicals called xenoestrogens. These substances mimic the effect of estrogen and other female hormones in the human body. They can directly lower fertility for both men and women, and can have other health effects as well. Other possible sources for xenoestrogens include pesticides, herbicides, and plastic containers (especially if heated)
When a woman gets older, there is a small increase in the chance for a variety of congenital defects in her offspring. It wasn’t thought that there was much of a similar risk for men. Now it appears that by waiting to father children, men are playing a game of genetic roulette all their own. Sperm counts and motility are directly affected by a man’s age. Since men are now typically waiting longer before starting families, their fertility is decidedly lower as well.
The current rate of decline in Western birthrates has likely masked the decline in male fertility. If this decline continues at the current rate, it is possible the human male could become completely infertile. If this were to happen, it is likely that a medical or technological fix would be forth-coming. If not, perhaps the Voluntary Human Extinction Movement will get their wish.
However, by isolating and controlling the chemicals thought to have the anti-androgen effects, along with the estrogenic chemicals, then it should be possible to remove these chemicals from the environment. Failing that, genetic intervention, possibly even cloning, could be brought into play. Such technologies would likely not be available for affected wild animal species, and they would likely become further victims of the Holocene mass extinction.
The indiscriminate pollution of our water supply and atmosphere can have unexpected results. Certainly no one intended that any of the chemicals dumped into the water supply would serve to sterilize human and animal populations. It may well be an important enough issue that we are forced to remedy our practices, and let the damaged populations start to repair themselves.