What Happened To Male Fertility?

Water pollution is a threat to male fertility: science horror fiction or fact?

In the Florida swamps, crazy things are happening to the alligators. Three-quarters of the eggs in some nests are dead, and even those that do hatch are producing strange offspring.

A thousand miles north in the Great Lakes, fish and fowl are suffering, too. Some fish are unable to reproduce, and many male fish show evidence of emasculation. The same is true of fish which live below sewage outfalls in English rivers.

Many years ago, Rachel Carson warned in her book Silent Spring of the effects of pesticides on the environment. Today, a new and equally alarming warning is being sounded by scientists who study the effects of hormone-like chemicals.

Sperm Counts Down By 50 Percent

The chemicals are being blamed for a whole series of hitherto unconnected observations. Sperm counts in men have fallen by 50 percent over the past 30 years, while testicular cancer has risen threefold. Among women, breast cancer has made an ominous but unexplained advance.

The thesis is that tiny quantities of chemicals, present in the water we drink, may be exerting a potent effect on the development of the reproductive system, particularly in men. So far, not surprisingly, the chemical industry and the water companies have dismissed the dangers as hypothetical and unproven.

That is not the view of the scientists who gave evidence to a Congressional committee investigating possible connections between breast cancer and the release of various chemicals.

Observing Changes In Human Sperm

The story begins with Dr. Neils Skakkebaek, who was the first to observe changes in human sperm. Not only were total sperm counts down by half since the 1930s, but he also noticed a growing number of abnormalities – sperm without heads, or with grossly distorted heads, some motionless, others hyperactive. The finding was alarming because one in seven couples suffer from infertility and it is more often the man than the woman who is the cause.

Other malfunctions of the male sexual system seem to be increasing at the same time. Undescended testicles, abnormalities of the penis and testicular cancer have all shown rises in the past 30 years.

In young men, testicular cancer is now the most common cancer of all, and although it can usually be treated successfully, the result often leaves the victim infertile.

The key that linked together all these observations was a class of cells that had been discovered more than 100 years ago in the developing embryo – the so-called Sertoli cells. The hormone secretions from these cells are the prompts that tell the fetus to develop as a male. The process is highly sensitive to the levels of estrogen, the female sex hormone.

The number of Sertoli cells determines, ultimately, the sperm count. If estrogen levels are too high, they fail to divide, leaving behind cells which Professor Skakkebaek has identified as the precursors of testicular cancer. When, in experiments in America, the hormone diethylstilbestrol (DES), a synthetic estrogen, was fed to pregnant mice, their offspring showed all the same changes.

The Human Experiment

Curiously, and tragically, there was also human experience to draw on. Between 1948 and 1971, millions of women were treated with DES to try to prevent miscarriage. Subsequently, many of their daughters suffered from cancers of the vagina. But what happened to their sons? Only two studies were ever done, but they showed that these men, too, had problems with their reproductive systems: undescended testicles, decreased sperm counts, and possibly also an increase in testicular cancer.

But it is one thing to show such changes in a population known to be exposed to high hormone levels in the womb, quite another to postulate that we are all running the same risk as a result of pollution.

A conference in 1991, organized by Theo Colborn of the World Wildlife Fund in Washington DC, who brought together the American studies of wildlife, concluded that levels of chemicals that may do adults no damage can have serious effects on developing embryos.

The risky chemicals are those that are either hormones or behave like hormones, blocking or disrupting the process of sexual maturation at a critical point. This is not a problem unique to America, as some experiments carried out in Britain by Professor John Sumpter of Brunel University showed.

Male fish were enclosed in cages immersed in 28 British rivers just below sewage outfalls. After three weeks, the male fish were found to be making in their bodies vitellogenin, a protein that requires the presence of estrogen and which only female fish should make. The first thought was that hormones excreted by women on the contraceptive pill, or on hormone replacement therapy, were getting into the rivers, but analysis failed to find them.

Professor Sumpter found his answer in some work done by a cancer researcher, Dr Ana Soto, at Tufts University. Working with breast cancer cells in culture, she had found they were dividing when they shouldn’t have been. The cells divide only in the presence of estrogens, and in this experiment, none were present: yet the cells divided.

Eventually, she discovered that a chemical component of the polystyrene tubes she was using was leaching an estrogen-like chemical. The chemical was an alkylphenol, ubiquitous in nature because it is one of the breakdown products of detergents, as well as being found in plastics and many other modern products.

So far, the case against alkylphenols remains unproven. In America, they have been found in low levels of drinking water, and as Ana Soto’s experiments show, they can behave like estrogens. In Britain the Water Services Association remains unconvinced, saying that at present there is no cause for alarm.

Experiments are now going on to observe whether fish kept in cages in reservoirs in Britain show the same changes as Professor Sumpter found in rivers, and the latest data suggest they do not.

The scientists interviewed by Horizon are not alarmists, and they believe they may be on to something very important. If they are proved right, the changes that will be needed will be enormous.

All chemicals that have any chance of reaching the environment will need to be tested, to see if they can behave like estrogens. New processes will be needed to clean up existing water supplies, and many products will need to be reformulated or replaced. The costs will be astronomical.

Leave a Comment