Sex on the Brain: The Biological Differences Between Men and Women
By Deborah Blum
Viking Press; 352 pages; $24.95
Blum's informants also mislead her in their appeal to chemistry as an ultimate explanation of sex differences. Blum masterfully explains why the effects of hormones are more complicated than pop science would have us think. They are produced by several organs in both sexes, may be converted into one another, and can have varying effects in different species, sexes, and individuals. The moral is that it is not hormones themselves but the neural circuitry, shaped by natural selection and modulated by the hormones, that explains our thoughts and feelings. The role of particular hormones may be like the role of green wires in an electronic device. The answer to the question "How does the device work?" depends on which wires connect which chips, not on the fact that a given wire is green.
This undermines explanations that assume ironclad effects of hormones. Take the idea that men became less competitive because women insisted on monogamy, which lowers testosterone. Natural selection is a resourceful tinkerer and could have rewired men's brains to respond to lowered testosterone in any number of ways, not necessarily by becoming less competitive. A better answer would appeal to the tradeoffs males face between investing in their current offspring vs. competing with other males to sire new offspring with other females.
In many circles, "The Biological Differences Between Men and Women" are fighting words. It seems a short step from saying that men and women are biologically different to saying that women are inferior. Moreover, if obnoxious behavior like aggression, rape, and philandering are biological, that would make them "natural" and hence good--or at least in the genes, where they cannot be changed by social reform. The result has been an angry rejection of the research Blum reports and an attempt to disseminate a feel-good alternative in which boys and girls are identical and infinitely malleable.
Blum rejects these non sequiturs. She does recount the sexist pre-1950s research, which is occasionally hilarious (as when scientists were obsessed with testosterone, which they treated as the essence of masculinity) and sometimes tragic (as when hare-brained theories led to horrifying surgical procedures on women). Blum dismisses bad research with the right touch of scorn, but does not feel a need to neutralize it with politically palatable agitprop. She believes that science can approach the truth, and that we are best off if we know it and deal with it thoughtfully--which she does. Sex differences, she points out, offer no support to invidious stereotypes, are not a guideline for what is right, do not apply to every individual, and never justify the restriction of opportunity. The ignoble impulses of both sexes are part of a complex mind that can often override them; and social arrangements, from individual marriages to entire legal systems, can change for the better.