Menstrual cycle alters face preference

Abstract

Women prefer slightly feminized male facial shapes¹. Such faces (Fig. 1a) are given positive personality attributions¹ that might correlate with actual behaviour². In contrast, masculine features seem to signal immunological competence³. Heritable benefits can be realized only if conception follows copulation, so women might be more attentive to phenotypic markers indicating immunological competence during the follicular phase of the menstrual cycle when conception is most likely⁴,⁵. Consistent with this hypothesis is the observation that women's preference for the odour of men with low fluctuating asymmetry (a correlate of testosterone-facilitated trait size and developmental stability) increases with the probability of conception across the menstrual cycle⁵.Symmetrical men report more extra-pair copulation partners⁶, and extra-pair copulation rates peak in midcycle⁷. Here we show that female preference for secondary sexual traits in male face shapes varies with the probability of conception across the menstrual cycle.