Birth order and sexual strategy

According to F. J. Sulloway [Sulloway, F. J. (1996). Born to rebel. New York: Pantheon], firstborns can minimize the diversion of parental investment to younger siblings by upholding their parents' beliefs, or the parental “status quo.” Maintenance of the status quo may translate into the pursuit of different sexual strategies as a function of birth order. Accordingly, Sulloway hypothesized that laterborns are more likely to pursue a short-term sexual strategy, whereas firstborns are more likely to pursue a long-term sexual strategy. The current between-family study tests this hypothesis with four predictions using self-reports of 438 college age men and women. Contrary to Sulloway's hypothesis, firstborns and laterborns did not differ in sociosexuality, a measure of short-term sexual strategy, or in desired age at first marriage, a measure of long-term sexual strategy. Consistent with Sulloway's hypothesis, laterborns desired more sexual partners than did firstborns at several future time intervals. Additionally, firstborns desired to have children at an earlier age than did laterborns, suggesting greater pursuit of a long-term sexual strategy by firstborns. Discussion addresses a methodological limitation of the current research and highlights the need for alternative methods for testing the hypothesis that sexual strategy varies strategically with birth order.