Biological bases of psychological sex differences

The mammalian process of sexual differentiation is briefly outlined. It is argued that in becoming girl or boy there are certain constraints and biases placed on the developing individual, some of these stemming from physiological bases, others from sensory-perceptual ones. These bases in turn affect the salience environmental factors for the two sexes. The different "behavioral styles" of boys and girls are thus a consequence of the transaction between the environment and these predispositions. The psychosexual anomalies are reviewed as instructive cases. Differences in neural organization and cerebral asymmetry are considered as further evidence of sexual dimorphism in humans.