BPA makes male mice less macho

BPA (bisphenol A) is a chemical found in many plastics that happens to mimic estrogen. Two recent studies have linked early-in-life exposure to BPA with feminized behaviors in adult male mice. In one study, BPA was fed to pregnant deer mice. The offspring were evaluated in terms of spatial and navigational abilities, as well as susceptibility to fear and anxiety. While males typically excel in such tests and females hesitate to explore, the male mice that had been exposed to BPA in the womb were "significantly compromised" in their abilities as compared to males that had not been exposed to the chemical. The female offspring did not appear to be affected by BPA. In the second test, mice were exposed to BPA in adolescence rather than in the womb. The male mice again exhibited feminized behavior, while females displayed abnormally exploratory behavior consistent with males. As one researcher commented, "These novel findings point to the fact that an early environmental exposure can manifest itself later in life...A likely mechanism is epigenetics."