Anybody following the literature in behavioural and evolutionary biology has noticed that sexual selection studies have dominated the journals in this field more than any other single topic for the last decade or so. Why has sexual selection been such a sexy topic? First, this boom coincides with important methodological innovations. The invention of DNA-fingerprinting, for example, has led to the development of new tools for the measurement of reproductive success and the outcome of mate choice. Similarly, the development of new comparative methods has stimulated numerous tests of evolutionary hypotheses that address key predictions of sexual selection theory. Second, theoretical advances of the theory itself have been astounding. There are at least three areas where new ideas have generated disproportional interest and significant new insights. They concern sexual conflict, sperm competition and the study of various indicators of good genes in the context of mate choice.

Sexual conflict has been recognised as an arena of intense intersexual coevolution driven by the fundamental genetic conflict between males and females. Many adaptations of both sexes are now being recognised as a result of an intersexual arms race. Using many examples from the primate literature, Smuts and Smuts (1993) identified sexual coercion as a behavioural mechanism employed by males to resolve the conflict between the sexes to their advantage. Sexual coercion continues to be one area of investigation where primatologists make important general contributions, especially with respect to the multiple pervasive effects of the risk of infanticide on behaviour and physiology, but other aspects of sexual conflict have remained virtually unexplored in primates.