Mothers are sensitive to men's beards as a potential cue of paternal investment.

Mating strategy theories assert that women's preferences for androgen dependent traits in men are stronger when the costs of reduced paternal investment are lowest. Past research has shown that preferences for facial masculinity are stronger among nulliparous and non-pregnant women than pregnant or parous women. In two studies, we examine patterns in women's preferences for men's facial hair - likely the most visually conspicuous and sexually dimorphic of men's secondary sexual traits - when evaluating men's masculinity, dominance, age, fathering, and attractiveness. Two studies were conducted among heterosexual pregnant women, mothers, non-contractive and contraceptive users. Study 1 used a between-subjects sample (N = 2103) and found that mothers had significantly higher preferences for beards when judging fathering than all other women. Pregnant women and mothers also judged beards as more masculine and older, but less attractive, than non-contractive and contraceptive users. Parous women judged beards higher for age, masculinity and fathering, but lower for attractiveness, than nulliparous women. Irrespective of reproductive status, beards were judged as looking more dominant than clean-shaven faces. Study 2 used a within-subjects design (N = 53) among women surveyed during pregnancy and three months post-partum. Judgments of parenting skills were higher for bearded stimuli during pregnancy among women having their first baby, whereas among parous women parenting skills judgments for bearded stimuli were higher post-partum. Our results suggest that mothers are sensitive to beardedness as a masculine secondary sexual characteristic that may denote parental investment, providing evidence that women's mate preferences could reflect sexual selection for direct benefits.