The evolution of female same-sex attraction: The male choice hypothesis

The evolution of female same-sex attraction: The male choice hypothesis. Menelaos Apostolou et al. Personality and Individual Differences, Volume 116, 1 October 2017, Pages 372-378, https://doi.org/10.1016/j.paid.2017.05.020

Highlights
•    Provides a new theory for the evolution of female same-sex attraction
•    Finds that men desire opposite sex partners who experience same-sex attractions
•    Finds that men desires their opposite sex partners to have sex with same-sex individuals

Abstract: Prevalence studies indicate that about one in five women experience some degree of same-sex attraction. The evolutionary origins of such attraction are not well understood. Accordingly, this paper proposed a theoretical framework where, during the period of human evolution, same-sex attractions in women were under positive selection. The source of positive selection has been male preferences for opposite-sex sex partners who experienced same-sex attractions. This theoretical framework was used to generate four predictions that were tested in two online studies which employed a total of 1509 heterosexual participants. It was found that heterosexual women did not desire partners who experienced same-sex attractions, but a considerable proportion of heterosexual men desired partners who experienced same-sex attractions. In addition, it was found that men were more sexually excited than women by the same-sex infidelity of their partners, and they desired more than women, their opposite-sex partners to have sex with same-sex individuals. Finally, participants' preferences were contingent on the seriousness of the relationships, with same-sex attraction to be preferred more in short-term than in a long-term partner. These findings were employed in understanding the evolutionary origins of same-sex attraction in women.

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Possible reasons for men to select bisexual wives:

Men with multiple wives, as opposed to men with one wife, face an elevated probability to be cuckolded, because they have to divide their sexual effort toward several wives so, inevitably, some of their wives will remain unsatisfied. They also have to divide their mate-guarding effort between multiple wives, which makes such effort less effective. If their wives experience same-sex attraction, they can satisfy their urges with other co-wives, who are readily available, reducing, in effect, the risk of cuckoldry (see also Kanazawa, 2016).

Another benefit that a man can accrue from an opposite-sex mate who is experiences same-sex attraction can be to gain access to other women. In particular, if a man's partner has sex with another woman, there is an elevated probability that he gains also sexual access to this other woman. In this respect, the same-sex attraction of his partner constitutes a window of opportunity for a man to have sex with other women without much mating effort, as this effort is made by his partner.

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the odds ratio (OR = 13.8) indicating participants to be more likely to respond that they preferred their short-term than their long-term partners to have same-sex contacts.

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the odds ratio indicated that men were 25.6 times more likely than women to prefer their partners to have sexwith same-sex individuals occasionally or frequently than never, a huge sex difference.

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The findings of the current research enable us to better understand the evolutionary origins of same-sex attraction in women. The presence in a high frequency of amalemorph that desires women who experience same-sex attraction as mates, would drive this trait to be in high frequency in the population. Alleles that predisposed for same-sex attraction in women, would be selected because women with such attraction would be valued more as partners by men than women who did not share such attraction. The presence of a male morph that does not desire such attraction explains why same-sex attraction has not been fixated in women. It would not pay for all women to experience same-sex attraction because most men do not find such attraction desirable in a female partner. In this respect, polymorphism in men's desires results in polymorphism in women's desires.

The findings of this study may also explain why heterosexual orientation with same-sex attraction is the most prevalent type of female same-sex attraction (Calzo et al., 2017). Men predominantly exhibited a desire for women who were heterosexual with same-sex attraction. This makes evolutionary sense, sincewomenwho are bisexual or homosexual may be less committed to the relationship with their opposite sex partners than heterosexual women with same-sex attraction
(Apostolou, 2016b). Thus, a woman who is homosexual for instance, would not be favored bymen, and, as a result,would face adverse fitness consequences. On this basis, female homosexuality is predicted to be in very low frequency, which is consistent with the findings of prevalence studies (Calzo et al., 2017; LeVay, 2010).


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Classical theory is: women search for bonds with other women to resist male coercion and violence (rape, infanticide, etc.).