Does The Contraceptive Pill Alter Mate Choice In Humans

Review

Does the contraceptive pill alter mate choice in humans?
Alexandra Alvergne and Virpi Lummaa
Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK

Female and male mate choice preferences in humans both vary according to the menstrual cycle. Women prefer more masculine, symmetrical and genetically unrelated men during ovulation compared with otherphases of their cycle, and recent evidence suggests that men prefer ovulating women to others. Such monthly shifts in mate preference have been suggested to bring evolutionary benefits in terms of reproductive success. New evidence is now emerging that taking the oral contraceptive pill might significantly alter both female and male mate choice by removing the mid-cycle change in preferences. Here, wereview support for such conclusions and speculate on the consequences of pillinduced choice of otherwise less-preferred partners for relationship satisfaction, durability and, ultimately, reproductive outcomes. Women’s dual sexuality In humans, female fertility increases gradually before ovulation and rapidly decreases thereafter. Conceiving is only possible during a brief 6-day period ending onthe day of ovulation (i.e. oestrous phase; [1]). However, women engage in and seek copulations throughout their cycles (i.e. extended sexuality [2]). This dual sexuality (conceptive and not conceptive) is suggested to have two distinct functions: one at the fertile cycle phase to obtain genetic benefits for offspring, and the other at the infertile cycle phase to obtain non-genetic materialbenefits [2]. Such a ‘dual strategy’ is generally observed in species where females must balance sires’ genetic benefits with costs of losing resources provided by their primary partners, owing to intrinsic and/or socio-ecological constraints precluding them from having both genetic and non-genetic material benefits provided by the same mate (Box 1). It is regulated by cycling physiological and subsequentbehavioural changes (Box 2), which can interact with mate choice. It is well documented that women prefer cues of mate non-genetic material benefits and assistance during less fertile periods and cues reflecting mate genetic quality or compatibility during more fertile periods (reviewed in Ref. [3]). Accumulating evidence suggests that ovulation also induces men to find women more attractive duringtheir fertile phase (reviewed in Ref. [4]). Overall, the ‘dual strategy’ of women’s sexuality is likely to have enabled ancestral women to make informed and, ultimately, adaptive decisions regarding with whom to pair and with whom to reproduce to maximize their reproductive success.
Corresponding author: Lummaa, V. (V.Lummaa@sheffield.ac.uk).

The oral contraceptive pill, used by 100 millionwomen of reproductive age worldwide (http://www.unpopulation. org), changes the hormonal state of the menstrual cycle by mimicking pregnancy (Box 2). Thus, mate preferences and choice could be modified by the use of such a pill (hereafter referred to as ‘the pill’; similar reasoning is applicable to any other hormone-based contraceptives, i.e. patch or implants, but empirical data concerning theirinfluence on mate preferences are lacking). Here, we review recent evidence to discuss the possibility that contraceptive pill use in women changes mate preferences in both sexes and affects subsequent mate choice and reproductive outcomes. Modern contraception has improved the quality of life worldwide, by reducing unintended pregnancies and maternal deaths [5] and, by enabling women to postponechildbearing, increased their educational level and subsequent role in modern economy [6,7]. Although we take a purely biological perspective towards pill use, we do not wish to undermine the crucial social and medical positive associates of this contraceptive method, which might act in opposite ways from those discussed here. Mate preferences vary across the menstrual cycle Both women’s and men’s...