BPA: The scary unseen chemical.

The hardest thing about being good to the earth is knowing what products you should and shouldn't use. This becomes increasingly more difficult when products we use every day turn out to be harmful to us and the environment.

Researchers have just linked prenatal exposure to bisphenol-A (BPA) with subtle, gender-specific alterations in behavior among 2-year-olds. Girls whose mothers had encountered the most BPA early in pregnancy tended to become somewhat more aggressive than normal, boys became more anxious and withdrawn.

In a paper out recently in Environmental Health Perspectives, Joe Braun of the University of North Carolina in Chapel Hill's team reports that the higher a mom's BPA levels were during her first 16 weeks of pregnancy, the more likely her child was to later show behavior somewhat atypical of its gender. Urinary BPA values later in pregnancy showed no link to behavior, Braun says, suggesting that the window of vulnerability to BPA's neurological impacts may be very early. Perhaps even before some women know they're pregnant.

So how do you begin to protect yourself and your unborn child against the harmful effects of BPA? Here are three ways to avoid BPA contamination.

Avoid aluminum food cans: BPA leaches into food, soups and sauces that are in cans. To avoid contamination, purchase these items in glass or cardboard containers, and purchase frozen foods. BPA seeps into liquids (such as sodas) at a slower rate.

Do not buy plastic #7: Polycarbonate plastic food containers often marked on the bottom with the letters "PC" recycling label #7. Polycarbonate plastics are rigid and transparent and used for sippy cups, baby bottles, food storage and water bottles.

Do not reheat food in plastic containers: Ceramic, glass and other microwaveable dishware are good alternatives. The heat makes it easier for BPA to get into your food.

While some of these changes may be a little too drastic for your home, choosing a few alternatives could save you and your family from harmful chemical exposure.