Whatever the motivation, this book's rhetorical force cannot be restricted to the mathematical modelling of evolutionary problems. The force and direction of the arguments throughout the book also draw heavily on the politics of social construction vs biological determinism. I will return to these chapters later. The middle of the book is occupied with laying out an extensive review of the literature on evolutionary or sociobiological accounts of homosexuality. It is in these middle chapters that McKnight presents his own hypothesis about the evolutionary nature of homosexuality.
Homosexuality presents a paradox to evolutionary theory.
This is not a new issue in evolutionary theory. Edward O. Wilson deals with it in his 1975 text Sociobiology, and as far back as the 1950s evolutionary theorists have been offering explanations for the genetic persistence of homosexuality. It is these 'homosexually-enabled straight men' that are at the centre of McKnight's explanation. Homosexuality survives, not because gay men, per se , are adaptive, but because the gay gene makes straight men more successfully heterosexual. McKnight hypothesises that this homosexual genetic loading endows some straight men with two crucial characteristics - enhanced sexual drive and charm.