Exposures in the womb or during adolescence can erase some masculine behavior
An ingredient in many clear plastics also renders some gender-linked behaviors plastic, at least in mice. Two new studies link feminized behaviors in adult males with exposures during development to bisphenol A, a weak estrogen-mimicking chemical. In one study, some behaviors in BPA-exposed females morphed into features characteristic of males.
The findings come from laboratory studies conducted in different species. Each experiment also exposed animals at a different time during development — one from the womb through weaning, the other during the rodent equivalent of adolescence and early adulthood. The trials therefore identify different periods during which the brain appears vulnerable to pollutants that mimic or alter the activity of sex hormones.
Because early BPA exposures left no lasting changes in sex hormone levels, the authors of each study note, the behavioral changes they observed in adulthood probably trace to an earlier rewiring of brain circu