Chapter 9 Summary and Analysis

Chapter 9 begins with a discussion of the, potential genetic basis of homosexuality. There is some evidence that a human being who has a particular gene on the X chromosome may, when it encounters the right kinds of environmental conditions, create a preference for sexual partners of the same sex. Whether or not this account of homosexuality is correct, it raises the question of whether or not and to what extent our reactions to those we find sexually attractive is the product of evolution. Our ideas of attractiveness and our sexual inclinations seem to be widespread, if not universal, and hence appear to be designed by evolution. This should lead us to believe that our notions of beauty, what we find attractive, is not arbitrary, but is rather the result of a long evolutionary process.

Men, for instance, universally prefer younger women...