Does Biology Underlie the Oldest Profession? Prostitution and Sex Disparities in John Behavior

Abstract

This study considers a biosocial explanation of why johns, the purchasers of commercial sex exchanges, are almost exclusively male. Trivers's theory of parental investment and sexual selection predicts that differential parental investment by biological sex will lead to divergent sex-based reproductive instincts. The sex bearing the larger parental investment will tend to be choosier, whereas the sex bearing the lesser investment will tend to be relatively indiscriminate and competitive for access to sexual resources. We hypothesized that men are more likely than women to offer objects of value in exchange for access to sexual resources. Using self-reports of sex-purchasing from Add Health data (N = 14,544), we found that maleness was a robust predictor of john behavior even after controlling for well-known criminogenic risk factors.

Acknowledgment

This research uses data from Add Health, a program project directed by Kathleen Mullan Harris and designed by J. Richard Udry, Peter S. Bearman, and Kathleen Mullan Harris at the University of North Carolina at Chapel Hill, and was funded by Grant P01-HD31921 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, with cooperative funding from 23 other federal agencies and foundations. Special acknowledgment is due Ronald R. Rindfuss and Barbara Entwisle for assistance in the original design. Information on how to obtain the Add Health data files is available on the Add Health website (http://www.cpc.unc.edu/addhealth). No direct support was received from Grant P01-HD31921 for this analysis.

Notes

¹The study was based on a survey of 612 men and 601 women. It included three transgender individuals, who were lumped into the female category for calculation purposes and were not disaggregated in reported findings. The small number would not significantly affect rate calculations. Additionally, the survey sample was from a sex-oriented conference, Sexpo, which might compromise the sample's external validity.

²John typologies have been attempted (Stein 1974; McKeganey and Barnard 1996), but they explain the forms of john behavior rather than the underlying causes thereof.

³As many criminologists attempt to explain both male and female crime via general theories, this study will attempt to account for such approaches utilizing empirically supported criminological variables as controls.

⁴Even in modern contexts, with the advent of birth control, such instincts would still affect human decision making. A fundamental tenet of evolutionary psychology is that these instincts arose over long periods spent in the environment of evolutionary adaptation.

⁵By contrast, though prostitutes are often stereotyped as females, more recent studies (Finkelhor and Ormrod 2004) indicate that prostitutes themselves tend to involve nearly equal proportions of each gender.

⁶It should be noted, however, that Trivers's theory has never been systematically applied to explain john behavior in multivariate contexts. Moreover, its applicability in human contexts remains controversial.

⁷Specifically, students were asked, “Have you ever been in a situation where are you are attracted to someone and you hint or promise to do something for them or give them something of substantial value, to increase your chances of having sexual relations with them?” (Kruger 2008, p. 207).

⁸This study's findings are in no way incompatible with gender effects.