Female hormones in the water supply may cause shrinking testicles and low sperm counts.
There are some strange things happening to men. Worldwide, sperm counts have fallen by more than a half over the past 50 years. In the 1940s, a “normal” sperm count was deemed to be 60 million sperm per milliliter of semen. Today, a man with 20 million sperm per milliliter is regarded as normal.
The long-term implications of such changes in male fertility could be serious. Worse, abnormalities of the male reproductive system are increasing. The incidence of testicular cancer has more than doubled, and undescended testicles are becoming more common. Malformations of the penis, known as hypospadias, in which the urethra, carrying the urine from the bladder, opens on the underside of the organ, are also on the increase.
Is Estrogen Affecting Semen And Sperm?
The cause of these changes may be our increasing exposure to the female hormone, estrogen, which triggers the development of the breasts and other sexual characteristics in women.
We now live in what one report describes as “a virtual sea of estrogens”, which may be having a subtle feminizing effect on men.
Large quantities of the hormone are present in cows’ milk, consumption of which has risen sharply since the war. It is also found in many plants and fungi, especially soya. Synthetic estrogens, used in the contraceptive pill, may have found their way into drinking water.
They resist being broken down by the body, unlike the natural form of the hormone, and may also survive sewage processing after being excreted in the urine. With millions of women now taking the Pill, there are anecdotal reports of estrogens being detectable in the water supply.
Pollution has also increased estrogen exposure. Many of the chemicals in industrial emissions have estrogenic effects in animals, causing defects in their male offspring.
Writing in the latest issue of the Lancet, Dr. Richard Sharpe and Professor Niels Skakkebaek suggest that the increase in environmental exposure to estrogens may be having damaging effects on fetal development.
Men’s Testicles Are Shrinking
Estrogen plays a role in normal male development, but it is produced naturally during pregnancy under controlled conditions at the right stage of growth. Extra estrogen from outside the body may switch off development at a crucial stage.
This could account for the shrinking size of men’s testicles and falling sperm counts.
“It is logical to assume that the changes in the male reproductive system have a common cause because they are all determined around about the same time in the early stages of pregnancy,” Dr. Sharpe says. “We know that many and perhaps all the reproductive tract abnormalities can be brought about by estrogen-induced changes during fetal development.
“If you want to take the worst-case scenario, increasing estrogen exposure could have a feminizing effect.”
The damaging effects of excessive estrogen during pregnancy were demonstrated between 1945 and 1971, when several million pregnant women were treated with a synthetic version of the hormone diethylstilbestrol, given to prevent miscarriage.
Studies of their sons have revealed decreased semen volume and sperm counts and an increase in abnormalities. The authors of the Lancet paper say “a strong mechanistic case” can be made for the link between estrogen and disorders of the male reproductive system, but further research is needed to confirm it. “If we can identify where the increased exposure is coming from, we may be able to protect the fetus,” Dr. Sharpe says.
Pollution Can Cause Low Sperm Counts
Some specialists, however, doubt whether the doses that could be obtained from environmental sources would be large enough, on top of those naturally produced during pregnancy, to have a pharmacological effect.
Other changes in the biology of the human reproductive system have also puzzled scientists. The birth rate for non-identical twins, the sort that comes from separate eggs and shares only a birthday, has fallen by a third since the late 1950s in Britain and most of Europe, but not in America.
Environmental pollution has again been blamed. Poland has seen the steepest decline in its twinning rate and is also one of the most polluted countries in Europe.
Cleaning up the environment may not only be a social benefit for our children’s children. It may be the only way to guarantee that our children are able to have children.