Oral Contraceptive Use in Women Changes Preferences for Male Facial Masculinity and Is Associated with Partner Facial Masculinity Hormones Affect Preference and Choice Authors

20 Millions of women use hormonal contraception and it has been suggested that such use may alter 21 mate preferences. To examine the impact of oral contraceptive (pill) use on preferences, we 22 tested for within-subject changes in preferences for masculine faces in women initiating pill use. 23 Between two sessions, initiation of pill use significantly decreased women’s preferences for male 24 facial masculinity but did not influence preferences for same-sex faces. To test whether altered 25 preference during pill use influences actual partner choice, we examined facial characteristics in 26 170 age-matched male partners of women who reported having either been using or not using the 27 pill when the partnership was formed. Both facial measurements and perceptual judgements 28 demonstrated that partners of women who used the pill during mate choice have less masculine 29 faces than partners of women who did not use hormonal contraception at this time. Our data (A) 30 provide the first experimental evidence that initiation of pill use in women causes changes in 31 facial preferences and (B) documents downstream effects of these changes on real-life partner 32 selection. Given that hormonal contraceptive use is widespread, effects of pill use on the 33 processes of partner formation have important implications for relationship stability and may 34 have other biologically relevant consequences. 35