Offspring Sex, Dominance, and Mating Behavior: Examining Evolutionary Mechanisms in Men and Women

Several lines of evidence suggest that parental dominance at conception results in male-biased sex ratios, but no studies have investigated the relationship between dominance and mate preferences in altering offspring sex in humans. Thus, the goals of my dissertation were to examine whether: a) dominance behavior, sexual restrictiveness, self-perceived masculinity and femininity, digit ratios, and hormone levels in men and women who had not yet had children were associated with their predicted sexes of future offspring (Studies 1 and 2); b) predictions for future offspring sex affected men and women’s mate preferences for dominance in the opposite-sex (Study 2); c) men and women’s predictions for future offspring sex were detectable in their facial characteristics (Study 3); and d) the sex of first-born offspring in actual parents was related to their dominance behavior, facial characteristics, and mate choice. The results of these studies provide partial evidence for the hypothesis that maternal dominance characteristics are related to the probability of male offspring, and that this is related to preferences for dominant male mates. Implications of these findings are discussed in the context of sex determination, parental ability to maximize their reproductive success through offspring, and sexual selection for male dominance and its associated characteristics.