The Truth Must Be in Here Somewhere: Examining the Gender Discrepancy in Self-Reported Lifetime Number of Sex Partners
Wiederman, Michael W., The Journal of Sex Research
Given the private and sensitive nature of sexual information, researchers typically must rely on self-reports of sexual activity and experience. Unfortunately, such self-reports are vulnerable to multiple forms of bias and unreliability (Catania, Binson, Van der Straten, & Stone, 1995; Catania, Gibson, Chitwood, & Coates, 1990; Catania et al., 1993; Clement, 1990; Wiederman, 1993), which may lead to researchers finding spurious relationships between sexual experience and other variables. One of the most robust relationships in research on human sexuality may be an example of this phenomenon. With remarkable consistency, men report a greater number of sexual partners compared to women (Oliver & Hyde, 1993; Smith, 1992a, b).
Substantial discrepancies between men's and women's self-reported lifetime numbers of sex partners have been documented among adolescents (e.g., Luster & Small, 1994) and college students (e.g., Lottes, 1993; McDonald et al., 1990; Walsh, 1993), as well as national samples of adults drawn from the United States (Laumann, Gagnon, Michael, & Michaels, 1994; Smith, 1991, 1992b), Britain (Wellings, Field, Johnson, & Wadsworth, 1994), France (ACSF, 1992), New Zealand (Davis, Yee, Chetwynd, & McMillan, 1993), and Norway (Sundet, Magnus, Kvalem, Groennesby, & Bakketeig, 1989). Apparently, this gender discrepancy is not new; Kinsey and his colleagues mentioned it with regard to data collected during the 1940s (see Kinsey, Pomeroy, Martin, & Gebhard, 1953, p. 683).
Rather than a small but statistically significant gender difference, the typical discrepancy in men's and women's lifetime number of sex partners is large by any definition. For example, in national samples, the mean number of sex partners for men and women, respectively, was 12.3 versus 3.3 in the United States (Smith, 1991), 9.9 versus 3.4 in Britain (Wellings et al., 1994), 11.0 versus 3.3 in France (ACSF, 1992), 10.2 versus 4.2 in New Zealand (Davis et al., 1993), and 12.5 versus 5.2 in Norway (Sundet et al., 1989). In populations that are more or less closed systems with an approximately equal ratio of men and women, such as the United States (U.S. Bureau of the Census, 1993), this apparent gender discrepancy does not make logical sense (Einon, 1994; Gurman, 1989).
Failure to address this seemingly illogical gender discrepancy has led some critics to question the validity of all sex research based on self-report (e.g., see Lewontin, 1995). Accordingly, noted sex researcher Ira Reiss (1995) observed that "this gender discrepancy in our surveys is a serious problem, and researchers need to find better ways of obtaining more valid responses" (p. 81). How is this gender discrepancy in self-reported lifetime number of sex partners to be explained?
Several possible explanations have been proposed, each of which is based on either potential sampling bias or potential response bias. The purpose of the current article is threefold: (a) to review the primary explanations that have been advanced for the apparent gender discrepancy, (b) to review existing data relevant to each proposed explanation, and (c) to present the results of two studies in which I further investigated the nature of the apparent gender discrepancy with regard to several explanations that have been proposed by previous authors.
Possible Explanations for the Gender Discrepancy
Potential Sampling Bias
Explanations for the gender discrepancy that rely on some form of sampling bias share the notion that it is extremely difficult, if not impossible, to obtain a truly representative sample in which to perform a comparison of men's and women's self reports. One reason is that, when it comes to sexual partners, no system from which one wishes to sample is completely closed (wherein members only have had sexual relations with other members of the specified group). So, to the extent that men or women have greater sexual experience with members outside of the group in which sampling takes place, the apparent gender discrepancy could be explained by one gender accumulating more partners from an unrepresented (not sampled) group. …