A chemical found in hard plastics -- such as CD cases, baby bottles, food-storage containers, and even electronics parts -- has been loosely linked to incidences of breast cancer. Popular opinion cautions that if we were not worried about this news yesterday, we should not be worried about it today -- because studies are preliminary and nothing is definitive at this point. But there are definitely two sides to the debate over how harmful these hard plastics may be.

The chemical in question -- a pseudo-estrogen called bisphenol-A (BPA) -- appears to be absorbed by breast tumor cells, according to a new study published in the August 28 issue of Chemistry & Biology. Previous studies have linked small exposures of BPA to prostate abnormalities in mice that suggest a link between the plastic chemical and human prostate cancer. Some studies even theorize that embryonic and fetal exposure might influence mental retardation and birth defects. And because this pseudo-estrogen is a synthetic material that in human cells can trigger estrogenic effects, breast cancer now comes up as a disease that may result from this questionable chemical.

Critics say that average levels of the chemical found in urine is infinitesimally small -- about one part per billion. Some say the results of this research come from in-vitro studies that one expert says can never fully explain human disease. Yet the real crux of the matter, according to another expert, is that we are surrounded by all sorts of chemicals that are pseudo-estrogenic -- not just BPA -- and it's the cumulative effects that we do need to worry about.