Spray gun: pesticides end up in the womb New Scientist 2 August 1997
'Girls who enter puberty early are, more likely to develop breast cancer"
GIRLS exposed in the womb to high levels of chemicals that mimic the sex hormone oestrogen go through puberty early, suggests a unique long-term study. Walter Rogan, acting clinical director at the US National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina, is monitoring children whose mothers were exposed during pregnancy to PCBs and DDE, a breakdown product of the pesticide DDT.
At a conference on environmental oestrogens in Arlington, Virginia, last week, Rogan presented preliminary data showing that the daughters of women with the highest exposures to these chemicals are reaching sexual maturity earlier. Chemicals that mimic oestrogen occur in everything from pesticides to plastics, and scientists are concerned that these "endocrine disrupters" could cause breast cancer and declining sperm counts. There are also suggestions that the chemicals interfere with fetal development. Between 1978 and 1982, Rogan and his colleagues tested hundreds of pregnant women living in North Carolina by measuring levels of DDE and PCBs in their blood and breast milk. They also tested for these chemicals in fetal blood collected from umbilical cords after birth. The team monitored 600 of the women's children as they grew older, sending them regular questionnaires that included line drawings of different stages of breast, genital and pubic hair development, so that the children could record which drawing most resembled their own bodies. Girls with the highest prenatal exposures to the chemicals entered puberty some eleven months earlier than girls with lower exposures. For boys, the onset of puberty was not affected by exposure in the womb to the chemicals. Few studies have followed children long enough to show how prenatal exposure to these chemicals affects them as they reach puberty. And scientists usually only collect data on pregnant women exposed to extremely high levels of oestrogenic chemicals after industrial accidents, says Michele Marcus of Emory University in Atlanta, Georgia. She says that Rogan's study population "is unique because it's women who were exposed through normal diet and environmental sources". Shanna Swan, an expert on the repro ductive effects of chemicals that mimic oestrogen at the California Department of Health Services in Sacramento, says the new findings are "very important and extremely interesting". The results raise health concerns, she says, because other studies have shown that girls who enter puberty early are more likely to develop breast cancer in later life. Nell Boyce, Washington DC
This article complements concerns about reproductive abnormalities in diverse animal species, including falling sperm counts in humans.
Our Stolen Future Theo Colburn Dutton
Feminization of Nature Deborah Cadbury, Hamish Hamilton.
The Feminization of Nature by Deborah Cadbury NS 30 Aug 97
ARE WE BEING poisoned by synthetic chemicals that mimic natural hormones? In particular, what about those which imitate the "feminising" hormone oestrogen? British television producer Deborah Cadbury has produced a well-written and meticulously researched overview of this topical and important question. The trouble is that, as Cadbury occasionally acknowledges, no one yet knows the answer. The evidence from wildlife is patchy, and the extrapolations to people uncertain. Those trends in human disease which are cited in support of the hypothesis remain contested by respected scientists. Yet Cadbury's text seems in thrall to a hypemonster. She recounts a story that is "chilling, gripping and deeply disturbing", just as the blurb on the book's jacket claims. The Daily Mail published extracts as "The Gender Threat". You understand why the American historian of hysteria, Elaine Showalter, regards The Feminization of Nature as the perfect "fin-de-siecle journalistic health scare". I should declare an interest: I too thought of writing a book about this subject. I interviewed the leading British scientific protagonists, n after Cadbury did. The has lots going for it: it scientific detective yo peopled with boffins b tling against the Establi ment. There is the whiff of government conspiracy and commercial cover-up. It even has sex: lesbian gulls, alligators with small penises, hermaphrodite river trout and men with falling sperm counts. And yet, another kind of book would serve the subject better, one that more determinedly sought that elusive "balance". There is far too much of the "true believer" about Cadbury's text. The real world seldom resembles an old-fashioned detective novel: undiluted goociies and baddies are almost as rare as tidy conclusions. Must popular science inexorably cast its characters as either heroes or villains? Sadly, another account of "endocrine disrupters", written from a similar perspective, is already on the book shelves.
Our Stolen Future by Theo Colborn and colleagues from the World Wide Fund for Nature (Little, Brown, F18-99, ISBN 0316875465) was published in Britain last year (reviewed by John Bonner, 4 May 1996). Its cover promises to tell us how "man-made chemicals are threatening our fertility, intelligence and survival" Disintegrating families, child abuse and increasing violence on the streets are all laid tentatively at the door of the chemical environment. Chemical contamination might also mean that a child "lacks the competitive edge to get into a top university". Putative threats to IQ became the campaign focus after WWF market research suggested that talk of declining sperm counts was a nonstarter: "In our focus groups, the women just laughed at the idea of low sperm counts. And the men denied it; they said it couldn't possibly be true of them," says Colborn. You get the feeling that the market research, rather than the scientific sort, is in danger of running the show. Despite its partisan approach, The Feminization of Nature is a' much better general guide to what oestrogens in the environment might be doing to wildlife and to us. Cadbury steers clear of the moral panic emanating from the hinterland of American science-wisely hoosing to ignore, for instance, the suggestion that the rise of the gay liberation movement in recent years could be the result of environmental oestrogens reprogramming the sexual orientation of fetuses in the womb. What's more, Cadbury's approach serves a valuable function. As the American science journalist Richard Harris puts it: "Although reporters are supposed to search out truth, we tend to err on the side of alarming, rather than reassuring the public. We are the watch dog barking in the night. It might not be a real intruder, but wouldn't you rather be alerted to the possibility?" Yet there is a price to be paid for this kind of coverage, Harris suggests: worst-case 2 scenarios may numb an already confused public. Are Cadbury and friends in danger of crying wolf once too often? I would much rather have seen Cadbury's investigative skills employed in exploring all the angles on this ongoing controversy. That way, readers might have come away not just scared, but with some insight into how science operates as a vital ingredient of late-20th century EuroAmerican culture. Gail Vines