Handedness and other laterality indices in women prenatally exposed to DES.

A group of 175 women who had been exposed to diethylstilbestrol (DES) prenatally were compared with 219 unexposed control subjects on four laterality indices: handedness, footedness, eyedness, and earedness. It was found that there was a higher incidence of left-handedness among the DES-exposed subjects than among the controls. It was concluded that intrauterine exposure to the synthetic estrogen DES disturbs the normal process of cerebral lateralization. The mechanism by which this takes place is still unknown.