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The Direct Reproductive Cost of Same-Sex Attraction: Evidence from Two Nationally Representative U.S. Samples

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Archives of Sexual Behavior
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Menelaos Apostolou at University of Nicosia
Menelaos Apostolou
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Same-sex attraction is associated with a direct reproductive cost, i.e., a reduced number of biological children. The current study aimed to assess this cost for different forms of sexual attraction (i.e., only attracted to opposite sex, mostly attracted to opposite sex, equally attracted to both sexes, mostly attracted to same-sex, only attracted to same-sex), using two large nationally representative datasets (N = 15,208) from the USA. The results indicated that same-sex attraction was associated with substantial loss in direct reproductive output. More specifically, significant differences between the different types of same-sex attraction were found: Exclusive and mostly homosexual orientation identities were associated with the highest direct reproductive cost, while mostly attracted to opposite sex orientation and bisexuality identities were associated with lower direct reproductive costs. In addition, bisexual women did not differ significantly from exclusively heterosexual women in terms of their reproductive output. The implications of these findings for the evolutionary origins of same-sex attraction are further discussed.
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Vol.:(0123456789)
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Archives of Sexual Behavior (2022) 51:1857–1864
https://doi.org/10.1007/s10508-021-02199-y
ORIGINAL PAPER
The Direct Reproductive Cost ofSame‑Sex Attraction: Evidence
fromTwo Nationally Representative U.S. Samples
MenelaosApostolou1
Received: 15 July 2019 / Revised: 16 October 2021 / Accepted: 16 October 2021 / Published online: 4 April 2022
© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2022
Abstract
Same-sex attraction is associated with a direct reproductive cost, i.e., a reduced number of biological children. The current
study aimed to assess this cost for different forms of sexual attraction (i.e., only attracted to opposite sex, mostly attracted
to opposite sex, equally attracted to both sexes, mostly attracted to same-sex, only attracted to same-sex), using two large
nationally representative datasets (N = 15,208) from the USA. The results indicated that same-sex attraction was associated
with substantial loss in direct reproductive output. More specifically, significant differences between the different types of
same-sex attraction were found: Exclusive and mostly homosexual orientation identities were associated with the highest
direct reproductive cost, while mostly attracted to opposite sex orientation and bisexuality identities were associated with
lower direct reproductive costs. In addition, bisexual women did not differ significantly from exclusively heterosexual women
in terms of their reproductive output. The implications of these findings for the evolutionary origins of same-sex attraction
are further discussed.
Keywords Same-sex attraction· Direct reproductive cost· Homosexuality· Bisexuality· Lesbianism· Sexual orientation
Introduction
Same-sex attraction motivates people to divert their mating
effort toward same-sex outlets from which children cannot be
born. Accordingly, it is expected that individuals who experi-
ence same-sex attraction would have fewer biological children
than those who do not (Vasey etal., 2014). Yet, the research
identifying the reproductive losses associated with same-sex
attraction is limited, and the current study aims to add to the
existing literature by examining how direct reproductive output
(i.e., number of biological children) varies across the different
types of sexual attraction (i.e., only attracted to opposite sex,
mostly attracted to opposite sex, equally attracted to both sexes,
mostly attracted to same-sex, only attracted to same-sex). Such
endeavor is important, especially for evolutionary theorizing.
More specifically, same-sex attraction appears to be an evo-
lutionary paradox as it impairs reproductive success by direct-
ing mating effort to same-sex outlets from which children can-
not be born. Same-sex attraction appears to have also a genetic
basis (Burri etal., 2011; Ganna etal., 2019), which means that
there are alleles which predispose for it, and were somehow
allowed by selection forces in the genepool. On this basis, most
evolutionary theories in the area proposed benefits which could
potentially balance the reproductive costs, allowing for this trait
to exist in the population (see Discussion for a review of some
of these theories).
Yet, the direct reproductive cost may not be as high as these
theories assumed. For instance, people who experience same-
sex attractions may have a strong preference to have children
(see Gates etal., 2007), which motivates them to have hetero-
sexual relationships in order to do so. Similarly, many people
who experience same-sex attractions are heterosexuals (Apos-
tolou, 2020; LeVay, 2016), and presumably direct most of their
mating effort to opposite-sex outlets. Accordingly, it could be
the case that same-sex attraction, when found in heterosexual
individuals, has little impact on the direct reproductive output.
Therefore, the endeavor of identifying the direct reproductive
cost associated with different types of same-sex attraction is
key in evolutionary theorizing in the area.
* Menelaos Apostolou
m.apostolou@gmail.com
1 Department ofSocial Sciences, University ofNicosia, 46
Makedonitissas Ave., 1700Nicosia, Cyprus
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... We found that gay men and lesbian women have lower fertility than their straight counterparts; this finding is in line with numerous other studies (Apostolou, 2022;Camperio Ciani et al., 2009, 2018Coome et al., 2020;King et al., 2005;Schwartz et al., 2010). We have also found that the difference in fertility of lesbian vs. straight women was smaller (τ = −0.03) ...
... than the difference in fertility of gay vs. straight men (τ = −0.23). This was also reported in Study 1 (but not Study 2) of Apostolou (2022). This association, with a similar magnitude, also held in the subsamples of atheist and Christian men. ...
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... Sexual attraction toward same-sex individuals has a heritable component (estimated around 0.32, ranging between 0.08 and 0.60; Alanko et al., 2010;Bailey et al., 2000Bailey et al., , 2016Burri et al., 2015;Kirk et al., 2000) and, despite its costly effect on direct reproductive output (Apostolou, 2022;Coome et al., 2020;Vasey et al., 2014), has persisted across different historical time periods and cultural contexts (Murray, 2002). For these reasons, same-sex attraction has puzzled researchers and despite much speculation and study, our understanding of its proximal or ultimate causes is still incomplete (Bailey et al., 2016). ...
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... In addition to potential within-sex benefits to women's same-sex attraction, it remains critical to consider the between-sex selection pressures. Men report considerably greater tolerance toward having a bisexual partner than women while similarly indicating that such infidelity from women is not necessarily egregious enough to terminate a relationship (Apostolou, 2022;Wang & Apostolou, 2019). This tolerance corresponds with evidence suggesting that women's same-sex attraction is less of a deal-breaker for men relative to men's same-sex attraction to women (Confer & Cloud, 2011;Lippa, 2005). ...
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Possible Balancing Selection in Human Female Homosexuality
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  • Mar 2018
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Background Few data exist regarding pregnancy in lesbian and bisexual (LB) women. Objectives To determine the likelihood of LB women becoming pregnant, naturally or assisted, in comparison with heterosexual women Search strategy Systematic review of papers published 1 January 2000 to 23 June 2015. Selection criteria Studies contained details of pregnancy rates among LB women compared with heterosexual women. No restriction on study design. Data collection and analysis Inclusion decisions, data extraction and quality assessment were conducted in duplicate. Meta‐analyses were carried out, with subgroups as appropriate. Main results Of 6859 papers identified, 104 full‐text articles were requested, 30 papers (28 studies) were included. The odds ratio (OR) of ever being pregnant was 0.19 (95% CI 0.18–0.21) in lesbian women and 1.22 (95% CI 1.15–1.29) in bisexual women compared with heterosexual women. In the general population, the odds ratio for pregnancy was nine‐fold lower among lesbian women and over two‐fold lower among bisexual women (0.12 [95% CI 0.12–0.13] and 0.50 [95% CI 0.45–0.55], respectively). Odds ratios for pregnancy were higher for both LB adolescents (1.37 [95% CI 1.18–1.59] and 1.98 [95% CI 1.85, 2.13], respectively). There were inconsistent results regarding abortion rates. Lower rates of previous pregnancies were found in lesbian women undergoing artificial insemination (OR 0.17 [95% CI 0.11–0.26]) but there were higher assisted reproduction success rates compared with heterosexual women (OR 1.56 [95% CI 1.24–1.96]). Conclusions Heterosexuality must not be assumed in adolescents, as LB adolescents are at greater risk of unwanted pregnancies and terminations. Clinicians should provide appropriate information to all women, without assumptions about LB patients’ desire for, or rejection of, fertility and childbearing. Tweetable abstract Review of likelihood of LB women becoming pregnant: LB teenagers at greater risk of unwanted pregnancies.
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Homosexual behaviour in primates
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Homosexuality is an evolutionary paradox in search for a resolution, not a medical condition in search for a cure. Homosexual behavior is common among social animals, and mainly expressed within the context of a bisexual sexual orientation. Exclusive homosexuality is less common, but not unique to humans. Poiani and Dixson invite the reader to embark on a journey through the evolutionary, biological, psychological and sociological aspects of homosexuality, seeking an understanding of both the proximate and evolutionary causes of homosexual behavior and orientation in humans, other mammals and birds. The authors also provide a synthesis of what we know about homosexuality into a biosocial model that links recent advances in reproductive skew theory and various selection mechanisms to produce a comprehensive framework that will be useful for anyone teaching or planning future research in this field.
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The Evolution of Same-Sex Attraction
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  • Jan 2020
This book provides a comprehensive analysis of the evolutionary origins of same-sex attraction, evaluating multiple existing evolutionary theories. It combines empirical findings with theoretical arguments in order to review evidence on the prevalence rates of same-sex attraction and determine its genetic and environmental basis. Among the topics addressed: • Attitudes towards same-sex attraction across human history • Assessing the weak selection pressures hypothesis of attraction • Assessing the male choice hypothesis of attraction • Evolution of same-sex attraction in men versus women The Evolution of Same-Sex Attraction will be of interest to academics and students of evolutionary and psychological sciences, filling a gap in literature on the origins of specifically same-sex attraction.
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The evolution of female same-sex attraction: The male choice hypothesis
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  • May 2017
  • PERS INDIV DIFFER
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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