Assessment of the relationship between the use of birth control pill and the characteristics of mate selection

Introduction: In recent research, scientists have begun to suspect that birth control pill use could interfere with key mechanisms that play a role when women choose a sexual partner. Many studies have shown that women, particularly during the most fertile days of their menstrual cycle, look for specific physical, psychological, and behavioral characteristics indicative of genetic quality in a short-term partner. Aims: Analysis of the psychometric properties of the Partner's Masculinity Index (PMI) scale. The scale was built to assess the degree of masculinity in hypothetical short-term partners. Methods: A total of 395 female Italian volunteers from Central Italy (M=32.9 years old, SD=8.58, range=18-50 years) completed the study. The psychometric properties of PMI were then evaluated. Main Outcome Measures: We administered the following self-report questionnaires: (i) PMI; (ii) Minnesota Multiphasic Personality Inventory-2 Masculinity/Femininity scale; and (iii) Demographic Questionnaire. Results: Exploratory and confirmatory factor analysis showed a four-factor structure for the PMI. Internal consistency of the measure, evaluated with the Cronbach's alpha, was satisfactory. Factorial ANOVA results showed that the group of nonpill users obtained higher scores on the PMI scale than the group of pill users (considering the fertile phase of the cycle). Conclusions: From an evolutionary point of view, changes in preference for indicators of genetic quality in a sexual partner are considered to be functional and adaptive. Pill use may have implications for both current and future generations. Directions for future research are discussed. © 2014 International Society for Sexual Medicine.