Are our gonads shrivelling? Is our sperm count falling, and are our sexual organs prone to cancers, malformations and misfunctions of a kind our fathers did not suffer? Are the man-made chemicals which are part of modern life to blame for these reproductive woes?
A nightmarish vision of a future Britain, whose middle-aged people have stopped bearing children and who are growing old in the bleak knowledge that their species will die out with them, is the backdrop for PD James's novel The Children of Men. But her fears are not just the product of one writer's imagination.
The subject has been the focus of a great deal of recent scientific study. In a report published last summer, the Medical Research Council's Institute for Environment and Health (IEH) concluded that the reproductive health of both animals and humans has indeed worsened over the last 50 years.
There is evidence that humans are more likely than their parents to contract breast or testicular cancers, and that men are more likely to suffer malformations of the reproductive organs which range from hypospadias-an anomaly in which the urethra opens on the underside of the penis-or cryptorchidism (undescended testes). Testicular cancer is now the commonest cancer among young men in Scotland. In the US, reproductive disorders have made it to the top 10 work-related illnesses listed by the National Institute for Occupational Safety and Health.
Evidence is also emerging that both the amount and the health of sperm produced by many groups of human males around the world is falling. A 1992 study published by the British Medical Journal showed that the average sperm count of men in several different countries had decreased by over 40 per cent between 1940 and 1990. The research was criticised for selection bias, but other studies back up the result. In a study of sperm donors in Paris, the first ejaculates of 1,351 men donated at a sperm bank were examined over the period from 1977 to 1993. The concentration of sperm declined on average 2.6 per cent per year.
Things are even worse in the animal kingdom. Hermaphrodite roach swim the River Lea in Britain. Male alligators in Florida's Lake Apopka have developed abnormally small sexual organs; their testosterone levels are only a quarter of the level of similar alligators nearby; they produce only half the usual number of viable eggs, and nearly half their young die before reaching the age of 10 days. Female western gulls in California are pairing off together because their males are dying early. Female molluscs studied in Plymouth are developing a small penis close to the right tentacle-a phenomenon known as imposex, which prevents eggs being released and reproduction taking place.
the causes
A few mavericks do suggest that the apparent increase in reproductive ailments and decline in the sperm count among humans are largely the result of new measurement techniques. But most of the scientific establishment does seem to believe that something is going on. The cause of the changes is the subject of fierce public debate. "The truthful answer is that we do not know, though we have our suspicions," says Richard Sharpe, of the British Medical Council. "Clearly it is something in our environment or lifestyle that has changed in the past 40-50 years. The chief suspect is exposure to certain man-made chemicals."
The IEH report blames many of the symptoms it lists in wildlife populations on the release of chemical pollutants into the environment. For reasons scientists do not yet fully understand, some of these chemicals begin to mimic the female hormone oestrogen as they break down, disrupting the living organism's hormone balance with an overdose of femininity. But the report was not prepared to blame oestrogen mimickers for the similar changes taking place in humans-at least, not yet. While it recognises as "plausible" the hypothesis that the same chemicals are at the root of the problem in humans, it says that there is not enough evidence to prove that damage to humans is "necessarily causally linked" to their exposure to these oestrogen-mimicking chemicals.
Green alarm
The green movement sees this as scientific shilly-shallying and government fudge. It does not want to wait for more research. The case it puts forward is simple: there must be a link between human reproductive problems and greater use of chemicals worldwide. Roger Lilley of Friends of the Earth says that the organisation is pleased that the government has commissioned the IEH to undertake further research, but fears that the chemical industry will be able to wriggle out of reducing its emissions. Greenpeace has been pursuing the same issue. "You're not half the man your father was," a recent advertisement said. Sure enough, the picture that went with it showed a man with a very small penis indeed. It was taken from a 15th century fresco painted centuries before the first man-made chemical pollutant entered the environment, but the message was clear.
The green campaigns have raised hackles in parts of the industrial, scientific and media worlds. "It is in their interests to cause public panic because that's how they get people into membership. We have to remember that Greenpeace and so on are multinationals themselves," says Elizabeth Surkovic of the Chemical Industries Association, which is implacably opposed to any instant bans.
Other influences on changes in the human body-such as stress, oestrogens synthesised naturally by plants or changes in the surroundings in which we live-should also be taken into account when examining the role of chemicals, Surkovic says. For example, there are higher levels of external oestrogens in soya than in man-made chemicals. Also, some of the suspect chemicals could only affect humans in rather bizarre circumstances. Phthalates, for example, which are used to make the coating around electricity wires more flexible, could only be absorbed into the body if you chew electric cable.
The Greenpeace ad has also attracted some sharp criticism. The shrinking penis idea came from 1993 research into children born of Taiwanese parents who had been poisoned by rice contaminated with PCBs-pollutants with oestrogenic properties-in the late 1970s. The research suggested that the penises of boys aged between 11 and 14 were shorter by a centimetre or so than those of boys in a control group.
But, as the Independent on Sunday commented: "The implication is that PCBs in the mothers caused a hormonal imbalance that affected the development of their babies... Well, no. It is not so simple as that. First, the doses of PCBs that the mothers of these boys received were colossal-the most conservative estimate is that they were several hundred times higher than anyone in this country is likely to come across through environmental contamination. Second, we do not dump PCBs into the sea. Production of these chemicals stopped here in 1986 and Britain is engaged in attempts to destroy its existing stocks, but not by sea dumping."
Dr James Lefanu, writing in the Sunday Telegraph, was even more dismissive of the whole "modern myth" that something in the water supply is having an adverse effect on male reproductive organs. He quoted a report from the New England Journal of Medicine in May 1995, which examined the effects on people born in the 1950s whose mothers were given an extra oestrogen called DES during pregnancy in the hope of avoiding miscarriages-but found no evidence that male sexual function or fertility had been damaged. "It is inconceivable that oestrogenic pollutants could be the cause of either the decline in sperm count or the rise in testicular cancer," he wrote, before concluding that there had clearly been no decline in sperm count at all and the only thing which had really changed since the 1940s was the measurement technique.
the oestrogen mimickers
The noise of this public exchange should not drown out the fruitful co-operation between science, industry and government in Britain directed at tracking down the causes of the problem and eliminating them. Although scientists are not yet prepared to say that oestrogenic chemicals are definitely the main cause of human reproductive problems, they are looking hard for clues. They share the Chemical Industries Association's opposition to banning suspected oestrogenic chemicals immediately. Their argument is that imposing a ban would mean lowering their guard by pronouncing the problem solved-without being sure this was the case. If it later turned out that some other product was causing the changes in sexual characteristics, the whole process would have to start again.
So far, four groups of oestrogen mimickers have been identified. What it is in their chemical make-up which actually fools the cells of living organisms into treating them like oestrogen remains unknown. Finding out whether, and how, oestrogenic chemicals damage humans could take years, says Professor John Sumpter of Brunel University, who works with Richard Sharpe. "It could be like the 'does aluminium cause Alzheimer's?' case a couple of years ago, which all seemed very big but has fizzled out because it's obvious there's really no link. This is more complicated because we don't know what chemicals we should be working on, nor do we know exactly what the effects are."
A big joint programme of study is being established, using funding from both chemical companies and the government. Professor Lewis Smith is doing research at the IEH. The Chemical Industries Association has been sponsoring Richard Sharpe's research, carried out by a team of half a dozen people, for just over a year. And its European body Esetoc, which is co-ordinating studies in different countries, is working with John Sumpter. On the government side the Department of the Environment, through the IEH, is organising a seminar in May for representatives of both science and industry. Meanwhile, the National Rivers Authority is trying to get the wool industry to reduce its use of detergents.
Of the four groups of chemicals identified so far as oestrogen mimickers, the first are the APEs and NPEs (short for alkalphenolethoxylates and nonolphenolethoxylates). They are used by many industries, especially the wool industry, and then dumped in rivers. Studies on fish downstream of the dumping sites show that concentrated doses of these chemicals have a feminising effect on fish. They are to be withdrawn altogether by the year 2000, but the Chemical Industries Association says it has shown its goodwill by voluntarily withdrawing them from consumer use years before the deadline.
Pesticides are the second group of chemicals causing concern. DDT, the most notorious, may have been banned, but it lingers on in the environment and breaks down into a powerful oestrogenic chemical. "Other pesticides which are still in use have been linked to falling sperm counts in agricultural workers, particularly those who work in greenhouses in places such as the Netherlands and Belgium. While those who work in a pesticide-free environment, on organic farms, have in one study been shown to have unusually high sperm counts, so there's a certain amount of evidence there," says Roger Lilley.
A third group are the phthalates, which make plastics more flexible. These are not only to be found in electric cable. They are also present in the materials used for food wrappings. Research cited by Friends of the Earth claims that they have not only contributed to the reduction of testicular size in animals, but can also migrate from plastic wrappings into fatty foods. Richard Sharpe's latest research tested five out of 40 phthalates and found that two had weak oestrogenic properties in the test tube and one had an effect during animal tests. Whether this would be reproduced in the natural environment remains to be seen.
The most recent entry on the list of suspects is bisphenol-A, used in the resin that coats the inside of some food tins. The case against bisphenol-A is that it leaks out into the liquid in the tin, again adding to the oestrogen levels of the food.
"The real problem is that people are exposed to tens of thousands of chemicals every day," says Lewis Smith. "It is extremely difficult to tease out individual chemicals or even classes of chemicals which are responsible for particular effects. There may be 'population effects' which it is very difficult to trace through to a particular individual. The causal links are very complex."
So, strong though the evidence is for chemical-related reproductive disorder, there remains considerable uncertainty about exactly where it is coming from. This allows some sceptics to dismiss it entirely, and some believers to convict particular chemicals without a fair trial.
