The truth in beauty.

• Author: Pennybacker, Mindy
• Position: Methods to protect your skin

Not for nothing did our ancestors worship the sun, the source of Earth's fertility and associated revels. What the ancients didn't understand, however, was the link between sun exposure and skin cancer. Whether you celebrate the season on a mountaintop or basking by the swimming hole, it pays to protect your skin. The key: read ingredient lists, and don't be caught napping at the expense of your or your children's health.

Sunscreens and Sunblocks. The skin is an absorptive organ, so it makes sense to use the least toxic products on it. Unfortunately, most sunscreens contain at least some iffy chemicals, including benzophenone, homosalate, and octymethoxycinnamate, shown in animal tests to disrupt hormones and affect development of the brain and reproductive organs. PABA (para-aminobenzoic acid) has caused allergic reactions, and padimate-O and parsol 1789 (avobenzone) have the potential to damage DNA. At the very least, these chemicals can irritate skin; they can also affect the health of aquatic ecosystems long after washing off.

A healthier choice is blocks that create a barrier against damaging UVA and UVB rays. These include zinc oxide and titanium dioxide, which are "much less likely than [chemical] sunscreens to penetrate human skin," according to biochemist John Knowland of Oxford University. Avoid all of these products on children under six months; instead, keep babies out of direct sun and use protective clothing and hats.

Chapsticks and Skin Creams. Dry skin and lips can tempt us to slather on moisturizers and balms. Are these safe? Not always. In September 2004, the European Union passed a rule banning hundreds of known or probable carcinogens, mutagens, or reproductive toxicants from cosmetics. Yet in the United States, neither cosmetic products nor their ingredients are reviewed or approved by the Food and Drug Administration before being sold.

Until ingredient bans are adopted worldwide, it's best to read labels. Many creams and chapsticks are based on petroleum, a nonrenewable resource; this includes petrolatum, a.k.a. petroleum jelly, which can cause allergic skin reactions and, if ingested excessively, diarrhea. Other problematic ingredients are glycol ethers, such as the common skin irritant propylene glycol, some of which have been linked in lab tests to birth defects and reproductive-system harm. The preservatives methyl-, butyl-, ethyl- and propyl-parabens are skin irritants that have also shown up in breast tumors. And...