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Scientists establish a link between mutations and sex reversal occurring in wildlife and an increasing load of man-made chemicals in the environment.

MATT PEACOCK: Welcome to Background Briefing. I'm Matt Peacock. And today 'Boys will be girls'. It's only in the last 50 years or so that the world has been swamped with a deluge of new chemical compounds - synthetic chemicals that are manufactured in the laboratory. And during that time, despite the many benefits that these chemicals have brought, scientists have also been watching anxiously for their potential side effects - the most obvious being that scourge of the 20th century: cancer. But there's another slower and more subtle effect. If cancer sometimes takes 10, 20 or even 40 years to manifest, what about the chemicals which affect future generations?

A phenomenon that's currently sweeping the world has many scientists gravely concerned. It's been called the feminisation of males. As new generations are born, the males in many species are developing more and more female characteristics, and it's something that's affecting species across the board: amongst humans, fish, birds, even alligators, as Kirsten Garrett reports.

UNIDENTIFIED: We were astonished at what we found. The things that we were seeing were so dramatic. We were actually seeing sex reversal. I mean, things were changing sex. At least 25 per cent, if not 30 per cent of the male alligators on this lake have some kind of abnormal phallus or abnormal penis. Mostly it appears the abnormality is small size, as much as a half or two-thirds reduced.

UNIDENTIFIED: With this size animal it's normally about twice this wide at least. It never has this hook to it like this.

PRESENTER: Similar changes to males of other species have been found in Europe and America, and now there are signs that human reproduction could be in trouble.

UNIDENTIFIED: Everything that we're seeing in wildlife has an implication for humans. I believe that we have the potential to have major human reproduction problems.

KIRSTEN GARRETT: 'Major human reproductive problems' against a soundtrack of apocalyptic helicopters and the bells of doom. What is this? media hype? greenie scaremongering? someone looking for a soft research grant? or 15 minutes of fame? Well, it's the staid and meticulous BBC TV and it raised questions about the fact that men today have very poor sperm, and that there's an alarming increase in both cancer of the testicles and prostate being reported; and there are more undescended testicles too, and that's only in people. Go to nature and you find deformed penises, males that lactate, hermaphrodite fish, Florida panthers flooded with female hormones, and bird colonies where the males are neutered and the females pair-bond. Feminisation of male creatures may be a by-product of the chemical age. Does it matter, a little less fertility? - maybe an antidote to all the testosterone in the world. Well, Congress, predominantly male, says 'Yes', and there's an inquiry on.

Cross now to Copenhagen where Dr Neil Skukkerbeck(?) sent the medical journals flapping with his hypothesis about why there is this apparent dramatic decline in human sperm.

NEIL SKUKKERBECK: It has been known for a long time that normal men do have abnormal spermatids, but the percentage of abnormal spermatids was just very, very high, and all too high to be considered normal in our eyes. It worried us and we were very surprised that we found a rather dramatic decline in semen quality. We found approximately a 50 per cent drop in numbers of sperm per ejaculate during the period in question, and also the volume of semen had declined during the same period.

KIRSTEN GARRETT: Scuggerbeck's hypothesis is that the problem is all those chemicals that behave like oestrogens in the animal body. These chemicals aren't meant to do that. They're meant to make the things we use in our daily life work better and smoother, more flexibly, cleaner, faster, cheaper. They are what make the 20th century life comfortable. But many of them behave, once inside the body, like the female hormone oestrogen, but with a vengeance. The body can't flush them out; they accumulate in body fat; they cross the placenta; and they may affect the development of embryo boys.

Critics have looked for flawed and flimsy work or mad obsessive maverick scientists, but find only more and more respectable and careful professors of this and that. And even the most cynical agree there is something going on.

Dr David Mortimer is scientific director of the Sydney IVF Institute.

DAVID MORTIMER: The problem is that sperm-counting methods have changed a lot; and, in fact, the methods that were being used in many laboratories 50 years ago were very inaccurate; and in fact, the methods used in many laboratories today are very inaccurate. However, I do believe that in general terms there is a reduction in the sperm quality, perhaps not in terms of its quantity. I think that there is a problem with a very large proportion of men - this is even in the men who come along as potential semen donors. We do see a lot of men there who would not be what we might have expected a few years ago. And I generally believe that having seen the same sort of picture here in Australia and in Canada and in the UK, that there is impairment in the production of normal function sperm by typical Westernised society human males.

KIRSTEN GARRETT: And you've said that the chemistry is there to show that it's certainly possible that the chemicals in the environment could be causing that effect.

DAVID MORTIMER: There are many published studies documenting to the effects of all sorts of chemicals. For example, there are many plasticisers or heavy metals like lead or cadmium to have very profound effects on the testes, and in fact the reproductive system is probably one of the most exquisitely sensitive parts of our physiology that will respond to such toxicants. The reproductive system, when it's developing in the embryo or the foetus, is a very sensitive system. All humans go through what's called the indeterminate stage of sexual differentiation where, effectively, both systems are present, and specific effects have to be exerted on the developing reproductive system to make it become male; otherwise, by default, it would become female.

So, if the wrong conditions exist, then there will certainly be a problem for the male in that there will be a de-masculinisation or perhaps even ultimately hermaphrodism.

KIRSTEN GARRETT: Sceptics were further quieted by the presence of reproductive biologist Dr Richard Sharp at Edinburgh, who worked with Scuggerbeck.

RICHARD SHARP: Neil was very convinced that this was the real drop. He's not a person who's given to over-exaggeration. He's very cautious. So when he conveyed his concerns to me, I thought it was real. And what this then suggested to us was that, well, something has happened. Something has happened to the process of sperm production - this process that we know very, very little about - and this effect is not a small effect; it's a big effect and it appears to be a general effect. So something is going on, something big, and we have no idea what is causing it.

KIRSTEN GARRETT: Originally, Scuggerbeck and Sharp threw new light on a particular point: the effect of synthetic oestrogens on Sertoli cells - the precursors to sperm production in all males. And in America that work was mirrored by some being looked at by the World Wildlife Fund. Talking here about laboratory evidence, Dr Thea Colborn(?) in Washington.

THEA COLBOURNE: In the laboratory, just one mil of dioxin - a very, very low dose to the mother on day 15 - to a pregnant rat will then .. her male rats actually will come out with about a 75 per cent sperm count reduction. They will be feminised in many ways: in behaviour, smaller penises, smaller testes, larger prostates, and then they're not producing their hormones in the normal way. Also there is definitely a good link between the damage to the Sertoli cells during exposure in the womb, and the Sertoli cells are the seed bank for sperm when the male matures. So, the male does not lay down as many Sertoli cells as he should, and consequently cannot provide the sperm.

For many years, we thought that the placenta provided a barrier and the brain had a brain barrier to a lot of chemicals, and we realise now that these chemicals can penetrate the womb, and this is an irreversible change that takes place.

KIRSTEN GARRETT: Because they affect the developing reproductive system.

THEA COLBOURNE: And we know now, of course, that the hormones are also .. the endocrine system controls how the immune system develops in the brain; so, consequently, what I like to describe this as - the architecture of these vital physiological systems - is not what it should be. And because there are so many very critical windows of time during embryonic development, and development is such a complex processes, you can't even predict what the outcome would be.

In the northern hemisphere - I wish we knew more about things below the equator but there's very little science coming out of there yet and very little chemistry that we can lean on - but in the northern hemisphere, we know of a large number of populations of animals where the animals aren't reaching sexual maturity, especially the males; so, they're not reproducing. The females have abnormal genitalia and reproductive tracts; so they're not reproducing as well.

KIRSTEN GARRETT: All this has long been known and well documented in laboratory animals, and now it's increasingly turning up in wildlife studies. Even the panthers in Florida were found to have undescended testicles.

THEA COLBOURNE: Since the US Fish and Wildlife Service announced that they could not find a Florida panther with fully descended testicles, they have looked and they have found a few that do have descended testicles, but also they've gone back and tested the oestrogen production in these animals - that is the female hormone production - and even those with descended testicles are producing far more female hormone than they should. And in several of the animals they're producing more female hormone, or oestrogen, than the female would. These animals are totally incapable of reproducing. So these males are basically sterile. And the alligators in the same area in Florida, they now have discovered are not developing normally. Again, these chemicals are present during embryonic development so that the alligators are born with shortened penises, and they're producing oestrogen like a female, and their testosterone production is very low.

KIRSTEN GARRETT: The man who did the alligators' work is Professor of Zoology, Louis Guillette. He says the problem goes far beyond Florida.

LOUIS GUILLETTE: I think we're talking about a worldwide phenomenon - not just in wildlife, but affecting humans as well. There's excellent work that is coming out of England; there's work coming out of the United States. In the United States there is clear evidence that contaminants have affected the reproductive biology in the endocrine systems in birds; in reptiles - primarily in alligators and turtles; in mammals, especially around the Great Lakes. In the Scandinavian countries there is excellent evidence that it's affect marine mammals there. In Canada as well, there is turtle work; there is marine mammal work; there is bird work. And in England there's some very, very nice work being done on fish.

How do we make the jump to humans? Much of what we see in the endocrine system, especially the work that I do when I examine the development of the reproductive system and the actual endocrine control or the chemical control of reproduction, the same hormones that influence reproduction in alligators, that influence reproduction, let's say, in a turtle are the exact same hormones that are involved in humans. So if, in fact, we see that we can disrupt the endocrine system or disrupt the development of the testis or the ovary in an alligator, many of the same hormones, in fact the same hormones are playing a very similar role in the development of human testes and human ovaries.

KIRSTEN GARRETT: One of the ifs and buts that I've heard about this is that the womb of the pregnant human female is the most oestrogenic environment on earth, and there is very little chance that any extra oestrogens would make any difference.

LOUIS GUILLETTE: Yes, let me explain. That's something which is true and it's also a partial misconception. When we talk about contaminants acting as hormones versus natural hormones, what we have to realise is that the human body and all these animals have evolved for aeons dealing with hormones in a natural setting. The question of course is, is why isn't the developing male foetus influenced by mom's circulating oestrogens? The answer to that is that mom has in her blood a series of proteins, binding proteins, which soak up - they're like a sponge; they soak up much of that free oestrogens that she has circulating her blood, so that very little crosses over the placenta and is exposed to the developing embryo.

We also have a series of systems, for example, plants make oestrogens - we call them phyto-oestrogens - and so when we eat plants or many different kinds of plants, especially, for example, soya products, you get phyto-oestrogens, plant oestrogens. The question is, is why aren't those effective? Well, again, we've evolved for aeons dealing with plant oestrogens. So, we have a system or many systems in our body that break down these plant compounds. We get rid of them. We can flush them out of our system.

The difference with man-made chemicals that we're spraying in the environment, which are acting as oestrogens or synthetic hormones, is that we don't have degradation pathways. We have no way to really break those compounds down, and they don't bind to the sponges or these proteins in the blood that soak up this extra hormone. So, the hormone - that is, these synthetic hormones, these synthetic chemicals - are allowed to cross the placenta, and, in fact, can get into the developing embryo, male or female. And it suggests that, yes, there could be a very serious problem for human beings.

The problems that we're describing: the ability to be fertile, the ability to produce offspring - that is not a catastrophic problem for the population. However, for the individual, if you're talking for humans, that is a catastrophic event if they can't have a child. And if many of the couples in a population can't have a child, then it becomes catastrophic for the population.

KIRSTEN GARRETT: Yes, because one of the things that the cynics say is 'Well, what does it matter?'. I mean, there are more men than we need anyway, and a little bit less testosterone in the world wouldn't hurt.

LOUIS GUILLETTE: Well, I mean, that .. I can take a very callous attitude as well and say: If this was only affecting humans, then we shouldn't really worry a lot about it because many of the environmental problems that we have, that we face today, are man-made. But the problem is that we do have to deal with it. It is a quality of health issue for humans and, more importantly, it's also .. or as importantly, it's a quality issue of health for wildlife, and I think we have to be concerned about that.

The problem that we face right now and the problem that I'm dealing with daily is that it's not surprising that these compounds can have an effect on the embryo. It's not surprising that we're seeing effects, let's say, in humans or in wildlife around areas that are highly contaminated. The question is, is we know that these chemicals are ubiquitous. They're occurring all over the world. We know that everyone is exposed to them; in fact, every baby born in the world is already carrying some kind of contaminant load. The question is, is what does that background load do? Does it have a biological effect? How extensive is its biological effect and what are the consequences for our grand kids?

KIRSTEN GARRETT: The 'Wingspread' meetings, which began a few years ago, pulled much of all this work together. The book of the scientific work has now been published by Princeton Scientific Press, and the scientists taking part signed a consensus statement.

We are certain a large number of man-made chemicals that have been released into the environment, as well as a few natural ones, have the potential to disrupt the endocrine system of animals, including humans.

The list of chemicals includes many that accumulate in living tissue, that are in common use, and that are persistent in the environment. Another book just out is Quick poison, slow poison, by Dr Kate Short. This is a summary of the high health costs of pesticides, and Kate Short comes out with both barrels blazing.

KATE SHORT: In my view there's been a deliberate orchestrated and financed campaign by the international pesticide industry to make sure they promoted what I call 'the myth of non-persistence'. In other words, Rachel Carson was right about DDT. There's only a few other really persistent pesticides like dieldrin, aldrin, chlordane and heptachlor, and which I may add are still used here in Australia, but the rest break down in the environment; so the Silent spring was no longer applicable. That's just not true. And the work I've done in my book on pesticide persistence I think will demonstrate that this whole issue of persistence of not only pesticides in our food, air and water and in our bodies, but of other of a wide range of industrial chemicals that may or may not mimic oestrogenic effects which are neurotoxic to both the unborn child, the newborn child, the developing teenager, along the same lines as lead. And that all these issues have to come and inform a really revolutionary approach to regulatory science.

KIRSTEN GARRETT: There are questions asked about why the same effects are not showing up in agricultural animals. David Lindsay is Professor of Agriculture in Western Australia.

DAVID LINDSAY: Well, no statistics are being kept and I believe that the reason they're not being kept is that there is no obvious signs that there are problems at this point, and while I'm very conscious of and concerned about the sorts of things that we're beginning to hear about in wild animals, it's certainly nothing in the domestic scene that is any cause for concern at this stage. The whole raison d'etre for domestication, I guess, is to make the animal far more capable of reproducing with surplus animals and, therefore, any very subtle changes will not show up.

KIRSTEN GARRETT: Is what you're saying that if there is problem, that domestic animals are in a sense genetically selected for their robustness?

DAVID LINDSAY: Oh yes, there's a very strong sense of that. They're very robust and are selected to do well on the sorts of feed and the sorts of feeding conditions that domestication has bought them.

KIRSTEN GARRETT: That's Professor David Lindsay in Western Australia. The point there is that wild animals live in a more sensitive balance where fertility problems show up more quickly and starkly. Another professor, John Sumpter, in biology and biochemistry at Brunel University outside London, added another point.

JOHN SUMPTER: The vast majority of agricultural animals never get anywhere near breeding, basically, particularly the males. Most of the effects that have been reported to date in wildlife are all males, particularly with testicular development, or the ducting system from the testes to the penis - the penis is too small or the ducting system has gone wrong, and this sort of thing. But actually, for example, the whole of the cattle, the whole of the sheep industry, only perhaps one in a thousand males gets to sexual maturity, if that, basically. The vast majority of that - the chicken industry - almost no animal gets to sexual maturity, or no male. So actually effects on males are not easy to pick up in the farming industry.

KIRSTEN GARRETT: John Sumpter is one of the key people in the worldwide interest in these issues. Some years ago, he studied fish in rivers that fed into the drinking water catchments in England. He found the fish were being feminised. The males were producing an egg-making substance and showing signs being intersex - hermaphrodite. His findings were kept secret; classified by the authorities for two years. Then the other stories came in.

JOHN SUMPTER: I hadn't really appreciated how many different scientists working in quite different fields - some working on wildlife, ourselves working on fish, but also people working on breast cancer, on testicular development in young boys - many different scientists from quite different angles have been reporting effects that they cannot easily explain. But one explanation which would fit all the information is that these effects are caused by exposure to man-made chemicals which, although not real oestrogens, can mimic the effects of oestrogens. Many people have called them false oestrogen. And this story has definitely really taken off in the last few years, and nobody can actually prove it at the moment, but a lot of very serious scientists, very good scientists across all sorts of scientific disciplines, think this is quite a viable hypothesis.

KIRSTEN GARRETT: One of the great reasons for scepticism is that what you might see happening in fish or laboratory animals or even birds, crocodiles, can't necessarily be applied to the human species.

JOHN SUMPTER: I think that's a very fair comment at the moment. As far as I'm aware, nobody has any information presently that can definitively demonstrate that these chemicals .. our people are being exposed to these chemicals at concentrations that would affect them. Having said that, there are quite a lot of studies done for different reasons which have looked at the accumulation of so-called false oestrogens in fat tissue in people, in milk - breast milk, for example - and you can find these chemicals in these situations.

So, it's not such a silly hypothesis as it sounds, basically. My personal opinion is that it certainly deserves very careful consideration. Nobody has any definitive information at the moment. The fisheries data is probably the best data so far. We do have direct data showing that oestrogenic chemicals can inhibit testicular growth of fish. We have very nice data on fish.

KIRSTEN GARRETT: Usually when a chemical or a substance is found to cause problems, it takes many years to scientifically prove the exact connection; in fact, a direct cause and effect is often impossible. Lead and asbestos are two products that were defended until they became indefensible, and it took 50 years before the dangers of tobacco were accepted.

JOHN SUMPTER: Yes, absolutely. I mean, tobacco is a good example. There are still people who don't believe that smoking causes cancer. This is unbelievable to me, but it's true. It took an awful long time to demonstrate conclusively to the majority of people that smoking causes cancer. So, I think that it will definitely take quite some time, years, before people have good data that either there is no evidence that they are affecting humans, or starts to provide evidence that this hypothesis holds water; and this is going to take some time. But I'm essentially encouraged in the sense that lots of people who I consider very good scientists take this hypothesis very seriously.

KIRSTEN GARRETT: It is a big jump, of course, from birds and fish and alligators to the human animal, especially when the science is complex and the cocktail of chemicals gets ever more mysterious. In Tuffe University, Dr Anna Sota was working on breast cancer research. She noticed the cancer cells were growing abnormally.

ANNA SOTA: It was an accident. Suddenly the cell cultures that I was studying, breast cancer cells, started to proliferate, or divide, like if they were in the presence of oestrogens. However, we were absolutely certain that we hadn't added oestrogens. But it was so clear that they were proliferating and that the only reason for that would be exposure to oestrogens.

We decided to investigate this problem as if a contamination by oestrogens had occurred. After four months we found out that the oestrogen was leaching from plastic tubes that we use to store serum. We contacted the manufacturer and the manufacturer provided us with several batches of his tubes. We could detect it to a point in which they changed the formulation of the plastic. However, when we tried to ascertain the composition of the raw material, we were denied the information because that is a trade secret. So, we decided to pursue that on our own because we considered that it was very important to know what this oestrogenic substance was.

KIRSTEN GARRETT: It was a chemical called nonylphenol and it's widely used in the plastic industry and also in detergents. It's very widespread. And it's this product which can cause the feminisation of fish. Researcher Tim Latham reports.

TIM LATHAM: Nonylphenols are used widely in many every day products. They are a breakdown of alkyl-phenolpoly-ethoxylates - APEs - a family of surfactants. Surfactants are compounds used in products that need to make surfaces wet; so they're in detergents, in paints, and pesticides, and weed killers, in lubricating oils, cosmetics and creams. Nonylphenols are also used plastic manufacturing and they're directly oestrogenic. But in Australia, little is known about their occurrence. No State in Australia tests for nonylphenols and nor are they listed in the National Health and Medical Research Council's drinking water guidelines.

KIRSTEN GARRETT: The jury is still out on nonylphenols, but they're only one of many.

2,4-D; 2,4,5-T; alachlor; amatrile; atrazine; metribuzin; nitrofen; tryflurolin; benomyl; hexachlorobenzene; mancozeb; maneb; metiram complex; tributyltin; zineb; ziram; beta HCH; carbaryl; chlordane; dicofol; dieldrin.

THEA COLBOURNE: The thing that is really disturbing is the fact that many products, plastics, these don't have chlorine in them. A lot of the other compounds had chlorine in them, although DES did not have chlorine in it. These plastics and products that we have been using we thought were benign. We thought they were very safe products. We're finding out now that they're actually giving off oestrogen-like compounds, and this is very disturbing and that's some of the work that's come out of England. They found that the detergents, the nonylphenols, the penta-nonylphenols actually are quite oestrogenic. The male fish were producing a product called vitellogenin which only female fish produce. If a male is doing that, he's not going to be producing much sperm. And this was the result of finding out that this material was coming from the detergents that people were using.

KIRSTEN GARRETT: One ubiquitous and suspect compound is chlorine, and there are about 11,000 compounds known as organochlorins, some of which can act as synthetic oestrogens. Chlorines are again used in most pesticides, in nearly all drugs and in every computer chip. They're used in dry-cleaning and in plastics, and as disinfectants. The American Public Health Association has now asked for more research and the Clinton Administration has called for an 18-month special study to look at the effects of chlorines on human health and the environment.

DDT; endosulphan; heptachlor; lindane; methomyl; methoxychlor; mirex; oxychlordane; parathion; synthetic pyretheroids; toxaphene; trans-nonachlor(?); aldicarb; DBCP; cadmium; dioxin; lead; mercury; PBBs; PCBs; pentachlorophenol; penta- to nonylphenols; phalates; styrenes.

And are all these chemicals used in Australia? We sent the list to Dr Kath Bowmer, Deputy Chief of the CSIRO Division of Water Resources, and we talked to her at a toxic algae conference in Adelaide. Her specialist knowledge is in pesticides.

KATH BOWMER: A lot of our crops are very much dependent on pesticide use. There's also quite a lot of pesticide used in industrial situations.

KIRSTEN GARRETT: And you've looked at the list of the ones that are coming out of the work on oestrogen mimics, synthetic oestrogens. Are we using any of those compounds here, any of those chemicals here?

KATH BOWMER: Yes, there's quite a long list, the list you gave me. Probably most of those are used in one way or another in Australian agriculture or industry.

I think the point is we really haven't got the guidelines to work on in this particular issue. I think in Australia we really need to do some integrating between health impacts and health science, between medicine and environmental medicine and resource management - that's the management of waters in catchments, sewerage treatment and drinking water quality treatment and so on. We have to bring those two areas of activity together.

KIRSTEN GARRETT: And what is happening in Australia's drinking water? Tim Latham takes a look.

TIM LATHAM: This week the New South Wales Health Department will release a report which shows one in three water authorities in country New South Wales failed to submit samples for testing in the early '90s. Pesticide monitoring overall is infrequent and isn't tailored to the timing or type of pesticide used in each area. The report states that in microbiological testing a number of locations fail existing health criteria on a continual basis. Last month, another report found 600,000 Victorians receive water which fails basic health department guidelines.

KIRSTEN GARRETT: The quantities needed before damage occurs are unknown, except in fish, and so is the cocktail that might build up after years of exposure. Work is also needed on the precise effect, at exactly what moment in embryo development. But there has already been one accidental experiment on human beings; that's the synthetic oestrogen given to women all over the world in the '50s and '60s. The compound is diethylstilboestrol - DES. At the time, people were not informed; medical records were not kept; and even tracing those at risk now is a huge problem; and some doctors dismiss it as a storm in a teacup, something that happened a long time ago to a few women, given huge doses.

But the figures are still coming in, and six to eight million is current. And research is gathering momentum only now, backed in America by the National Institute of Environmental Health Sciences. Director there is Dr John McLaughlin, one of the signatories to the 'Wing Spread' consensus.

JOHN McLAUGHLIN: Well, you're exactly right that there was somewhere between two to six to eight million pregnant women treated with DES - diethylstilboestrol - between 1948 and 1974. Certainly a form of cancer of the vagina is associated with DES exposure in young women whose mothers took this medication. But there are other changes in the shape of the uterus; the shape and action of the fallopian tubes; fertility that affect a large number of women. Abnormalities of the reproductive tract are much, much more prevalent than the effects on fertility overall seem to be rather pronounced.

In terms of sons, it's still not clear what the overall picture is going to be. Early result show that there was an increase in undescended testicles and smaller than normal size of the penis. Animal studies suggest that there would be a decrease in sperm count and perhaps some abnormality to the prostate. That hasn't been seen yet in humans, and it's not clear that it will be seen. But I think both males and females certainly are affected. I think also the DES-exposed population takes on added importance as leading indicator of what could happen with perhaps less potent environmental oestrogens.

KIRSTEN GARRETT: But I've been astonished to discover that in Australia, first of all, people were told that it was not given here at all. Then three or four women came out and said 'Well, I had it', and now it appears there are several hundred Australian women who had it.

JOHN McLAUGHLIN: There are DES action groups or cancer networks worldwide. It's interesting your comment about Australia, because a colleague of mine, when he went back to Finland, was told also that there was no use of DES. But after he checked through records, found out that in fact DES had been used in Finland, and this may be the case in other developed countries. One of the mottos of one of the DES advocacy groups in the US is 'Ask your mother', and I think it's important for people to actually know whether or not they've been exposed to DES and to have an informed sense of what their overall health risks might be.

KIRSTEN GARRETT: There is a DES action group in Australia as well. That was Dr John McLaughlin in Washington, and in Melbourne, Professor David De Kretser of Monash is one reproductive biologist who has some knowledge of DES and other synthetic oestrogens.

DAVID DE KRETSER: Many women who were given diethylstilboestrol to prevent the loss of pregnancy way back in the 1950s and '60s, they are well-known to have developed a high incidence of vaginal cancer. And the men, or the male offspring of those women, have also shown abnormalities in the development of certain parts of their male reproductive system. So there is a case for oestrogens, but I think what these papers have done is to heighten our awareness of the whole problem. And I know that a number of groups, including our own, are starting to focus a bit more on environmental factors and try and develop models which might enable us to identify some of these factors.

KIRSTEN GARRETT: All this comes as no surprise to Kate Short. She's been blowing the whistle on it for decades. We know too little about all the chemicals we're using she says. Her own work concentrates on pesticides, many of which mimic oestrogens.

KATE SHORT: Scientific work that's been done has indicated that Australians in fact bear a higher body burden of these fat soluble chemicals than other comparable countries, and that this body burden hasn't significantly declined since the early days, the Silent Spring days of the early 1960s.

KIRSTEN GARRETT: I keep coming across the problem of actually measuring them. It seems that some of them we can't measure for because we don't know how, or we haven't got the technology yet, and others are unmeasurable in that the amounts that might be having an effect are so small.

KATE SHORT: Well, that's right. I also think the point that I've made in my book that's very important is that many of the pesticides that are routinely used on fruit, vegetables, foods et cetera and end up particularly in our water supply, but also in our foods, are not regularly tested in the market basket surveys. Now this is a historical thing and it relates partly to the ability to do the tests quickly and cheaply.

KIRSTEN GARRETT: Because in one survey of pesticides in Adelaide's water supply, they were only able to test for 30 per cent of the known pesticides used in that catchment area.

KATE SHORT: Well, that's right and that's similar, for example, the work I did in the cotton area and the work that was done by State pollution control people in the cotton area a few years ago. It couldn't be seen as a finite result. You couldn't get the total pesticide load because you really were only monitoring for a handful of the 450, I think - 450-odd registered pesticides. So, I mean, maybe we don't need to measure them all. We need to get some sort of total load equivalent of value developed in our regulatory science.

What the public, what society in the late 20th century has to come to understand that we've only really had less than 100 years of organic chemistry of the chemical industry and that we're really babes in the wood. And we've had, you know, a million years of development and we've had a very, very short time to come to grips with what we're dealing with, and I think it's in that context that we can understand the problem and go forward.

KIRSTEN GARRETT: Meantime the debate continues. Are men being feminised? Is there a true fall in sperm quality and count? What is the link between that and the beginnings of the chemical revolution? There's a doubling, even doubling of prostate and testicular cancers and an increase in breast cancer. Is there any link there? What exactly is the mechanism that leads to panthers with undescended testicles? to alligators with small penises? intersex gulls? hermaphrodite fish? and laboratory rats with scrambled reproductive systems?

Emeritus Professor of Reproductive Biology and Endocrinology at the University of California in San Francisco, Penti Siteri(?), has studied oestrogens all his life, and he says these questions require urgent attention.

PENTI SITERI: I don't want to be an alarmist, but I can't think of a more serious threat. My gut feeling is that the potential problem is of such a magnitude that it demands we address it in the most serious way possible.

KIRSTEN GARRETT: It's interesting that the chemical companies have not decried this story as mindless scaremongering or the outrageous and self-serving rantings of a few greenies. They are rather co-operating with researchers. John McLaughlin.

JOHN McLAUGHLIN: In the US there's been a surprising amount of interest in where we are with the whole idea of chemicals in the environment that can work like female sex hormones, like oestrogens. There's certainly been interest in the United States Congress. A variety of companies and industries are very interested in evaluating what's the best way to measure hormonal activity of a variety of these chemicals.

KIRSTEN GARRETT: A bit of a surprise with this issue is that there is not more resistance from, say, the chemical companies or the people who would traditionally oppose this sort of thing. I'm thinking of the outcry there was when we wanted to take lead out of petrol or reduce tobacco smoking, or asbestos; you know, they were all resisted like mad. This one seems to be general agreement that there probably is a problem.

JOHN McLAUGHLIN: Yes, I think the chemical companies want to make sure that if there are any risks, and we're not sure what they would be, that they're ahead of the game.

KIRSTEN GARRETT: And do you think that that's because they are more politically astute or because the science is irrefutable?

JOHN McLAUGHLIN: I think the science is very strong that many chemicals that we haven't even thought of before can work like oestrogens. There's also a lot of good data saying this is what oestrogens can do to humans, either early in development or to adults or during puberty. And I think that even though there's not a strong connection to human health at the present time, I think the data is saying that these compounds could work this way is convincing and persuasive enough that the issue is more: How do you deal with it? How do you take care of it? How do you protect people? - rather than saying that this data doesn't make any sense.

KIRSTEN GARRETT: Dr John McLaughlin of the National Institute of Environmental Health Sciences. We also made contact with the Chemical Industry Institute of Toxicology in Washington. Dr Tom Goldsworthy.

TOM GOLDSWORTHY: I think there is a great deal of data that supports that hypothesis up to this point, and there is concern and data that suggests that we should be studying this to understand it, so we can better clarify if it is indeed a risk.

KIRSTEN GARRETT: And the chemical companies themselves, I'm told, are in fact co-operating and quite interested in directions it might take.

TOM GOLDSWORTHY: Yes. Oh certainly. Our institute, the Chemical Industry Institute of Toxicology, is sponsored by chemical companies and they're certainly interested. And I know many of the companies themselves are doing research because, certainly if chemicals are contributing to this, we have to understand that and understand exposure, dose and response issues.

KIRSTEN GARRETT: Meanwhile, the evidence rolls in.

THEA COLBOURNE: Remember the Taiwan episode where the rice oil became contaminated with PCBs and the mothers ate the rice oil, and years after they had stopped taking .. eating the rice oil, their children have been affected. Their children have 5-point IQ deficit, which appears to be going to be the same in the children from around the Great Lakes whose mothers ate that fish. Also they have now measured the penises on those boys, and at puberty their penises are significantly shorter. The girls are shorter in stature and they also have found that there are certain domains of conceptual thinking that can separate boys from girls, and it was very interesting to find out in a recent paper that was just released about two weeks ago here in Washington, that the boys in this study definitely thought like girls when it came to the spatial thinking. It was quite interesting. So, you know, all we have is this continually increasing evidence building up to the point where, where and when do we assume the responsibility to say 'no more', that we have got to do something about this, and that's very difficult when you're dealing with economics and jobs and the immediacy of feeding your family.

KIRSTEN GARRETT: And all the comforts of First World living.

THEA COLBOURNE: And that's right. Exactly. If we were only dealing with one or two chemicals, we could handle maybe one or two added to the environment, but we don't know any more. We've got such a mix out there. So it's a very, very difficult thing to weigh. And I'll tell you quite frankly, we're never going to do it by controlling from one product or going for one industry or going for one sector within industry. This is society's problem. Everyone has got to think about it. We have to go right down to the personal level and think 'What am I doing?'. Consumption is one of the biggest driving forces behind this problem.