Some sunscreen ingredients have been shown to mimic estrogen.

Several common ingredients in sunscreens have been shown to act like estrogen. One test-tube study showed that breast cancer cells grew faster in the presence of such compounds.

Another study showed that sunscreen ingredients are absorbed through the skin and can be measured in the urine (Journal of Investigative Dermatology, July 2004). The significance of this finding for adults remains controversial, but the authors warn that young children may be vulnerable to hormonal disruption from such sunscreens.

Sunscreens that contain physical blockers such as zinc oxide or titanium dioxide don't have hormonal effects and are safe for young children and people with sensitive skin (the Lancet online, May 3, 2007).

Courtesy of LA Times