The incredible shrinking man.

Theo Colborn is alarmed. Her wildlife research in the Great Lakes region has convinced her that common chemicals widely used in American homes and industries are affecting males of all species, causing dramatic reductions in fertility and a growing number of gross deformities in the male anatomy, including shrunken penises and testicular problems.

"I think we have reached the point where there are measurable changes in humans and the environment from the chemical soup we carry around in us," says Colborn, a zoologist who earned her Ph.D. from the University of Wisconsin and is now a staff scientist for the World Wildlife Fund. "There are too many parallels between what's going on in the field and in the lab."

Colborn believes popular chemicals used for growing food, treating and purifying water, manufacturing plastics, and producing pulp and paper are damaging the endocrine, immune, and reproductive systems of animals. and the chemicals are creating these effects at exposure levels far below accepted safety limits--thresholds typically set for measuring cancer risks.

By far the most troubling impacts occur in the womb, where the chemicals circulating in the mother's body may deliver a profound punch to the developing embryo and fetus. Colborn calls this a "transgenerational effect." Any fetal damage is permanent and irreversible, although the results may not appear until early adulthood. And, she notes, the pollutants could have been absorbed years earlier by the body, only to wreak havoc during childbearing.

"The effects are being seen in the offspring more than the parents," says Colborn. "The problem is that people don't understand that these chemicals are affecting fertility, the doorway to population."

From her office in Washington, D.C., Colborn is mobilizing the scientific community. Twice in the past three years she has convened an international gathering of scientists at the Wingspread conference center in Racine, Wisconsin, to discuss chemical pollution, animal health, and fertility. All of the researchers carried pieces of the puzzle from their own specific investigations to the conferences. As they compared notes, they were startled by the emerging picture and they began to speak out.

"Every man in this room is half the man his grandfather was," Louis Guillette told a group of lawmakers at a recent Congressional hearing. Along with the other Wingspread scientists, the University of Florida researcher was in Washington to spread the word about fertility threats in the environment. Guillette's remarks referred to the fertility investigations of Neils Skakkebaek, a Danish scientist, and other Europeans. According to Skakkebaek, sperm totals for men have declined 50 per cent since the 1940s. Skakkebaek's conclusion is based on the analysis of sixty-one sperm-count studies in which 15,000 men participated.

It's the action of chemical pollutants on the endocrine system that defines how they are thought to harm life. "The endocrine system is the sister to the nervous system," explains Guillette, a specialist in reproductive endocrinology.

The endocrine system regulates the body's functions over the long run through the release of various hormones, much as the brain and nervous system govern the body from moment to moment.

The Wingspread scientists call the offending chemicals "endocrine disrupters." In most cases, the hormonal pollutants fool the body into thinking they are estrogen, the primary female hormone. (A few of the pollutants, however, directly sabotage the actions of male hormones.) Males, like females, produce estrogen, though in far smaller amounts, and both possess estrogen "receptors" in their bodies. Like a key to a lock, the fake estrogens invade and occupy the receptor sites.

Guillette uncovered one of the most spectacular cases in Florida. Between 1980 and 1985, the alligator population crashed in Lake Apopka, the state's third-largest freshwater lake. In every nest, something was wrong with the gator eggs. Surviving juvenile males had abnormally low testosterone levels and abnormally high amounts of estrogen. "In other words, they were feminized," says Guillette.

Guillette's team also observed that 25 per cent of males had shrunken penises that would never allow them to reproduce. Guillette blames a 1980 pesticide spill for the sexual warping. Lake Apopka's alligator population has yet to recover, and Guillette's researchers are now finding similar problems in other Florida lakes.

In the Great Lakes region, sixteen predator species, including mammals, reptiles, birds, and fish, show reproductive, thyroid, metabolic, and behavioral problems, according to Theo Colborn. All of these difficulties, she says, can be tied to endocrine disrupters.

The Wingspread scientists and the World Wildlife Fund have compiled an initial list of forty-five widely used chemicals that possess endocrine-disrupting effects. The roster includes thrity-five agricultural pesticides and a mix of ten other common metals and industrial by-products, as well as plastics.

If there's one common link on the Wingspread list of known hormonal pollutants, it's chlorine. Chlorine is a key component in twenty-three of the forty-five substances. Given that chlorine is extremely widely used, and is a $70 billion-a-year industry, this is an ominous finding.

"What we've in fact done is spray the globe with endocrine-disrupting compounds," says Guillette. "Am I upset? Sure I'm upset. I can't confirm right now that every person or thing is at risk, but for me there is tremendous concern."