You probably don't realize it, but all kinds of popular products are likely to be upsetting your hormones. This effect, known as "endocrine disruption," can be quite shocking. The chemicals in question are widespread, their effects sometimes devastating. Both humans and animals are at risk. Perhaps the worst part is, they're so ubiquitous, no one can avoid them completely.

I might not know about endocrine disruptors, either, except a doctor I interviewed five years ago tipped me off. Suddenly, news about endocrine disruptors seemed to appear everywhere. Shortly thereafter, my mother coincidentally gave me a cassette tape of a lecture by Theo Colborn, who turned out to be a guru on the subject.

The tape really got me. On it, Colborn said one in 125 boys born in the United States in 1993 - the latest date for which data was available - were born with hypospadias, or misplacement of the urinary outlet, roughly double the number in 1970. "Whoa! That's a lot of birth defects!," I thought. But why? The Centers for Disease Control and Prevention, the source of the data, said the cause remains unknown. That may be true.

But the stunningly high incidence of a defect that can require surgery - and in some cases can't be corrected at all -- shifted me into high gear. Researching further, I read that "experiments with laboratory animals reveal that hypospadias can be repeatedly and reliable (sic) produced by exposure to several endocrine disrupting chemicals, including DDE and vinclozilin, a commonly used fungicide," according to the Web site of Colborn, world-renowned zoologist and co-author of "Our Stolen Future," a 1995 book about chemicals in our environment that mimic our human hormones.

Some argue that we don't need to worry about endocrine disruption because we don't know for sure these chemicals are affecting humans, and, even if they are, their effects aren't significant. Most of the research on the subject has been done with animals, not humans, they note. But, as a nursing mother who regularly takes her kids to the zoo, I am well aware I am a mammal. The fact that so much research has been done on other mammals is precisely what worries me.

Endocrine disruptors can affect many different aspects of the body: reproduction, immunity, intelligence, growth, metabolism and mood. Reproductive disorders resulting from endocrine disruption, for example, include low sperm counts, birth defects of reproductive organs, feminization of males, and early onset of puberty. Fetuses are particularly vulnerable. If a woman is exposed to the disruptors during pregnancy, her unborn child may be affected, leading to either birth defects or adult cancer in her child.

Chemicals that can be considered endocrine disruptors have spread around the world through industrialization. They include heavy metals like cadmium, arsenic, lead and mercury. They also encompass a dizzying array of modern manmade substances. Some of the products that can contain endocrine disruptors include insecticides, herbicides, brominated flame retardants, resins lining food cans, plastic softeners, cosmetics, hairspray, and dental sealants.

These chemicals have dispersed widely. "Tragically, no children today are born chemical-free," note Colborn, Dianne Dumanoski and John Peterson Myers in "Our Stolen Future." Various studies show pesticides can be found in amniotic fluid, placental and umbilical cord blood, and breast milk. "Even Inuits living a traditional lifestyle in remote regions of the Arctic have not escaped," they wrote. "The pollution has come to them."

Any kind of grasp on endocrine disruption is quite new. Only since the late 1980s have scientists really begun to unravel the mysteries. It was Colborn who brought the issue to the fore. Now an internationally renowned environmental hero, Colborn was a grandmother who had just finished her doctorate when she put together diverse pieces of a puzzle. Poring over studies conducted on wildlife around the Great Lakes, she discovered a pattern of abnormalities among fish, mammals and birds, particularly the predators at the top of the food chain. While the scientific community was so focused on cancer, Colborn saw something else. All the abnormalities had a hormonal link.

Today, Colborn's realizations have spawned research projects worldwide on the hormonal impacts of a vast array of chemicals. Many scientists have come to realize that very small amounts can be much more toxic than previously thought (even down to parts per trillion). They are examining the timing of toxic exposure, with special emphasis on fetal risk.

The regulatory process, however, is not yet equipped to deal with endocrine disruption. Regulators just haven't caught up with the latest science. "Although EPA has some data on endocrine-disrupting pesticides, insufficient scientific data are available for most of the estimated 87,000 chemicals produced today to allow for an evaluation of endocrine associated risks," notes the EPA on its own Web site.

As part of the Food Quality Protection Act of 1996, Congress did direct the Environmental Protection Agency to develop a "screen" that would look for endocrine disruption. A decade later, however, no EPA screen has been finished. "We have gone more slowly than we either hoped or expected," says Bill Jordan, senior policy adviser in EPA's Office of Pesticide Programs. "Our hope is to have a validated screen by the end of 2007," he told me. When a screen is ready, regulators will start by testing pesticides. The thousands of other potential endocrine disruptors will have to wait.

There is no way we can change what has already coursed through our bloodstream. But, in light of cutting-edge research, it's imperative we minimize endocrine disruption in the future. Many simple changes in our behavior can add up. Reducing exposure to endocrine disruptors can only help our own bodies, and it may make a huge difference for our children. There's actually a lot we can do.

For practical advice, stay tuned for Part II in the August edition of PeaceSigns.

For more information:

Find out about Professor Tyrone Hayes' research on frogs, hormones and pesticides at <http://www.nationalgeographic.com/emerging/tyroneHayes.html>

Go to Colborn's Web site at <http://www.ourstolenfuture.org> and the EPA's Web site on endocrine disruption at <http://www.epa.gov/scipoly/oscpendo/index.htm>

Read "Our Stolen Future," by Theo Colborn, Dianne Dumanoski and John Peterson Myers; also read "Living Downstream: A Scientist's Personal Investigation of Cancer and the Environment" by Sandra Steingraber.

Check out the Environmental Working Group report on "Across Generations: The Chemical Pollution Mothers & Daughters Share and Inherit" at <http://www.ewg.org/reports/generations/newsrelease.php>

For some of Colborn's latest research, see <http://www.ehponline.org/docs/2005/7940/abstract.html>. Colborn is a professor at the University of Florida, Gainesville, and president of The Endocrine Disruption Exchange at PO Box 1407, Paonia, CO 81428 (Tel: 970-527-4082).

To keep up with the latest research on environmental health, see the journal Environmental Health Perspectives at <http://www.ehponline.org/docs/2006/114-6/toc.html>.