Effects of prenatal exposure to diethylstilbestrol (DES) on hemispheric laterality and spatial ability in human males.

Ten males exposed to diethylstilbestrol (DES), a nonsteroidal synthetic estrogen, during gestation were compared to their matched, unexposed brothers on measures of brain hemispheric specialization for processing nonlinguistic spatial information and cognitive abilities. DES exposure was associated with reduced hemispheric laterality and lowered spatial ability. These data provide direct evidence of a relationship between brain laterality, spatial cognitive ability, and prenatal exposure to hormones in human males. Further, the implications of these findings for understanding sexual differentiation of the human brain are discussed.