Change sex with soya

Review: THE FEMINISATION OF NATURE: Our Future at Risk by Deborah Cadbury, Hamish Hamilton pounds 17.99

The trouble with the environment is that it's one damn chemical after another. They drift around the world; they ensconce themselves exactly where they will do the most damage; they curl out of microwave trays and seep into drinking water. Some of them are made not in industrial plants, but in vegetable ones. You can't even trust nature these days.

Deborah Cadbury's title is misleading, since this is not a literary exercise about the social construction of nature. Instead of gender studies, it confronts the reader with fish that change sex, alligators with malformed genitalia, falling human sperm counts, and cancers of reproductive organs. Scientists suspect the factor common to all of these may be the hormone oestrogen, which turns out to have a host of imitators. The list of chemicals which can bind to the body's oestrogen receptors is now so long that one could be forgiven for thinking that anything with "oxy" or "yl" in its name is a threat to human fertility. And scientists are beginning to wonder whether oestrogen is just the tip of the iceberg; whether synthetic chemicals are disrupting the work of other hormones as well.

The effects of hormone imitators are not necessarily straightforward. Soya contains chemicals that mimic oestrogen, but the food actually appears to confer protection against cancer. According to recent surveys, average sperm counts are twice as high in New York and Finland as they are in California and Denmark. Despite dramatic findings from a number of research groups, some critics question whether the fall in sperm counts is real. Something is gravely amiss, but we are still a long way from a full picture.

On the other hand, this story has been in the public eye for several years. Deborah Cadbury admits as much with her subtitle, "Our Future At Risk", which acknowledges last year's landmark book, Our Stolen Future by Theo Colborn, Dianne Dumanoski and John Peterson Myers. The two books present many of the same exhibits, the alligators featuring prominently, and the cast lists are much the same. Both describe themselves as telling a "scientific detective story". If we lived in a culture in which scientists didn't have to be compared to police officers in order to gain the public's attention, we might be a little nearer to sorting this problem out.

Cadbury herself publicised the issue four years ago, in a Horizon television programme called Assault on the Male, and draws heavily in this book on material gathered for the documentary. Thankfully, she doesn't use any of the pictures. Her narrative is unsettling enough as it is. Sometimes it passes from disturbing to distressing - and that is entirely proper. This story needs to be repeated, and its grimmer details dwelt upon, until it provokes action instead of just unease. Cadbury's book does offer useful perspectives of its own, such as its accounts of the work of Richard Sharpe and Niels Skakkebaek, the two most prominent European researchers in this field. But where it really justifies itself is in its ability to keep the reader on edge.

Until alarm calls like these raise some political pressure, we're pretty much on our own. Cadbury notes that most of the scientists she interviewed have changed some of their domestic practices - filtering water, avoiding food packaged in plastic, keeping soya out of children's diets, even putting vegetables in paper bags to keep them from contact with plastic carrier bags. Like any other worried citizen, they seem to be casting round for something useful to do. But as scientists, they are aware that these steps may be no more than hollow gestures. You can change from milk in plastic bottles to glass ones, observes John Sumpter, who first observed fish changing sex in the River Lea, but the glass bottles may have been washed in detergents containing oestrogenic chemicals. He washes his fruit and veg, but admits he can't point to any evidence that this reduces his exposure. And there are so many products that might turn out to contain oestrogen imitators, from face cream to petrol.

It took long enough to establish that smoking causes disease and to to translate that knowledge into action, even though the mechanism was relatively straightforward. The more people smoked, the more likely they were to become ill. Hormonal disruption may not be apparent for decades after the damage is done. Low sperm counts may be the result of exposure before birth, when the cells that later generate sperm are being formed. The case Cadbury puts together suggests that there may be men developing prostate cancer in the next century whose mothers took synthetic oestrogens when pregnant in the 1950s. If the politics of smoking are anything to go by, those men will be seeing more of their lawyers than their doctors.