Reproductive toxins are substances that poison the reproductive system. They can cause damaged sperm in men, infertility in women and early puberty. They can also damage growth in children and fetuses. Heavy metals like arsenic, or the lead recently found in some imported toys, are the most common offenders.

Recent research by Kim Dietrich at the University of Cincinnati College of Medicine found a link between lead contamination in fetal development or during early childhood, and adult antisocial behavior leading to arrest. Even a tiny amount, a five- microgram/decilitre increment in prenatal or childhood blood lead levels, was associated with a 26 per cent increase in the rate of arrest for violent crimes.

Mercury is another good example, and can be found in everything from the fillings in our teeth, to "silent" light switches. In the book Slow Death By Rubber Duck, one of the authors ate tuna for every meal for three days. Simply upping his tuna intake catapulted the mercury in his blood to levels that would be dangerous to a pregnant woman.

Possibly the least understood and most terrifying are the endocrine disruptors. Unlike other chemicals, endocrine-disrupting chemicals (EDCs) can cause damage even at extremely low levels of exposure. These chemicals mimic natural human and animal hormones. When released into nature, they can either block natural hormones, or exaggerate their effects.

Tony Clement, when he was federal health minister, banned baby bottles containing bisphenol A (BPA) because tests on mice show that it mimics estrogen, and can affect early childhood development. Another well-known EDC is polychlorinated biphenyl (PCB).

Even if we restrict their use, many EDCs persist in the environment by accumulating in the food chain through the fats of mammals.

EDCs have been found in the breast milk of both humans and animals, even those who live far away from any obvious pollutants. Significant EDC contamination can come from the air, drinking water, and particularly skin through contact with chemicals in household and industrial products, cosmetics and clothing.

With EDCs the poison is not the dose; it's the timing. These chemicals can profoundly affect fetal or early child development at critical growing stages. They can cause emasculation, improper development of reproductive organs, including incomplete development of testes, and early-onset puberty in both animals and humans.

Even more sinister are the implications for women. New studies have shown that regular exposure to EDC's during pregnancy -- even at low doses -- can potentially affect the next two generations, since the eggs for the next generation are already being developed in the fetus. In other words, your grandmother -- in some ways -- was carrying you inside her body.

Poisons passed on

"What people are realizing now," says Mae Burrows, executive director of Toxic Free Canada, from her office in Vancouver, "is that you can't just look at the lifestyle of the 45-year-old woman who is developing breast cancer; you have to look at what her grandmother was exposed to."

As a consumer, I can only hope to curb the sea of toxins in which my daughter has been swimming since she was in utero. Unseen substances around her may have already affected her physical growth. We have been playing with powerful chemicals in everything from the fuel for our cars, to the teething toys we gave our children to suck as babies.

In the next article, we will look at how we can use Canada's labour laws to educate ourselves on toxic ingredients, and reduce the mass consumption of unnecessary chemicals in our environment.

On Wednesday, 'Toxics: The Right to Know, Part 2.' The Tyee looks at how we can use our labour laws to curb chemicals to safe levels, and how to decide what "safe" means when it comes to some of the most toxic ingredients made by man.