"An individual's development is not merely a battle between nature (genes on the inside) and nurture (experience or learning on the outside)", Rogers argues, "but is a dynamic interweaving of processes within a system which is inseperably the organism and its environment" [emphasis added]. Rogers cites many examples of how the brain responds to environmental inputs--often by changing its biochemistry and even its structure. A rat, for example, "living in a complex social environment has a thicker cortex than one raised alone". From this and many other examples Rogers argues that the different social environments in which girls and boys are raised may alter their brain structure and function.

This is a genuinely radical idea supported by recent evidence. If only the same were true of the deterministic fantasies of the sociobiologists: the sociobiological argument is that sex differences are unalterable by the individual and arose out of evolutionary necessity. On neither count does Rogers find the evidence for this position satisfactory, and her criticisms and counter-arguments are cogent and sharply expressed.

Sexing the Brain leaves the reader with a vivid sense of the crushing difficulty of working on science without prejudice. --Simon Ings