Familial patterning and prevalence of male androphilia among Istmo Zapotec men and muxes

Abstract

Male androphilia (i.e., male sexual attraction to other adult males) is known to cluster within families. Some studies demonstrate that male androphilia clusters in both the paternal and maternal familial lines, whereas other studies demonstrated that it clusters only in the latter. Most of these studies were conducted in Euro-American populations where fertility is low and the sexual orientation of male relatives can sometimes be difficult to ascertain. These two factors can potentially confound the results of such studies. To address these limitations, we examined the familial patterning of male androphilia among the Istmo Zapotec of Oaxaca, Mexico––a high fertility, non-Euro-American population where androphilic males are known locally as muxes, a third gender category. The Istmo Zapotec recognize two types of muxes––muxe gunaa and muxe nguiiu––who typify the transgender and cisgender forms of male androphilia, respectively. We compared the familial patterning of male androphilia between muxe gunaa and muxe nguiiu, as well as between gynephilic men and muxes (both cisgender and transgender forms combined). Istmo Zapotec muxe gunaa and muxe nguiiu exhibit similar familial patterning of male androphilia. Overall, muxes were characterized by significantly more muxe relatives than gynephilic men. This familial patterning was equivalent in both the paternal and maternal lines of muxes. The population prevalence rate of male androphilia was estimated to fall between 3.37–6.02% in the Istmo Zapotec. This is the first study that has compared cisgender and transgender androphilic males from the same high fertility population and demonstrated that the two do not differ with respect to the familial patterning of male androphilia.

Prevalence of Sexual Orientation Across 28 Nations and Its Association with Gender Equality, Economic Development, and Individualism

“…Similarly, we suggest that to the extent that the prevalence of heterosexuality, bisexuality, and homosexuality is consistent across cultures, sexual orientations likely have biological underpinnings (Bailey et al, 2016). At the same time, to the extent that the prevalence of self-reported heterosexuality, bisexuality, and homosexuality varies across cultures (e.g., reported rates of male homosexuality range from about 1.5 to 5%; Gates, 2011;Gómez, Semenyna, Court & Vasey, 2018;Semenyna, Patterson, VanderLaan, & Vasey, 2017;Whitam & Mathy, 1986), such variations may be due, in part, to social and cultural influences. If systematic cross-cultural variation exists in sexual orientation prevalence rates, it may be possible to identify specific cultural factors that are associated with such prevalence rates across cultures.…”

Inter-sexual mate competition in three cultures

“…Given that gender non-binary males represent 2–5% of the male population in both Samoa and the Istmo Zapotec [ 18 , 36 ], it is perhaps surprising that 43% and 85% of women in each respective culture report having ever experienced inter-sexual mate competition. This seeming disparity highlights two important likelihoods.…”

“…From the perspective of psychobiology, the most well studied third-gender males are the Samoan fa’afafine [ 15 ] and the Istmo Zapotec muxes of Oaxaca, Mexico [ 16 ]. These individuals are almost always exclusively androphilic (i.e., sexually attracted and aroused to adult males), and display the same correlates of male androphilia documented among Western gay men, such as gender atypicality in childhood, more older brothers, more androphilic relatives, and a prevalence rate of ~2–5% [ 14 , 17 , 18 ]. Gender non-binary males such as these rarely, if ever, engage in sexual activity with each other, but instead engage in sexual activity with masculine males (i.e., men).…”

The relationship between fraternal birth order and childhood sex‐atypical behavior among the Istmo Zapotec muxes

“…Despite differences in gender presentation, previous research has found that when compared to Istmo Zapotec gynephilic men, both types of muxes have more androphilic male relatives (Gómez et al., 2018), have elevated indicators of separation anxiety (Gómez, Semenyna, Court, & Vasey, 2017), and recall more sex‐atypical behavior during childhood (Gómez Jiménez, Court, et al, 2020), with transgender muxes recalling even greater CSAB than cisgender muxes . However, a study of family size found that both male and female relatives of (transgender) muxe gunaa have significantly more offspring than those of gynephilic men, whereas no such differences were found between the relatives of gynephilic men and (cisgender) muxe nguiiu (Gómez Jiménez, Semenyna, & Vasey, 2020).…”

“…Although robust evidence for the FBOE has been found cross‐culturally, research demonstrates that only 14%–29% of androphilic males owe their sexual orientation to the FBOE (Blanchard & Bogaert, 2004; Cantor, Blanchard, Paterson, & Bogaert, 2002; Swift‐Gallant, Coome, Aitken, Monks, & VanderLaan, 2019). Nonetheless, each biological older brother a male has increases the odds of being androphilic by around 34% (range: 8%–68%) over the baseline rate of male androphilia (Apostolou, 2020; Blanchard & Bogaert, 1996a; Blanchard & Lippa, 2007; Blanchard, Zucker, Siegelman, Dickey, & Klassen, 1998; Ellis & Blanchard, 2001; Green, 2000; Khorashad et al., 2020; King et al., 2005; Kishida & Rahman, 2015; Schagen et al., 2012; Schwartz, Kim, Kolundzija, Rieger, & Sanders, 2010; Semenyna, VanderLaan, & Vasey, 2017; VanderLaan & Vasey, 2011), which is around 2%–5% of the male population (e.g., Gates, 2011; Gómez, Semenyna, Court, & Vasey, 2018; Leser, 1961; Semenyna, VanderLaan, Petterson, & Vasey, 2017; VanderLaan, Forrester, Petterson, & Vasey, 2013; Whitam & Mathy, 1986). In other words, assuming that each older brother increases the odds of male androphilia by approximately 34% (the average of 13 studies) and that a random male without older brothers has at least 2% chance of being androphilic, having one older brother would increase the probability of male androphilia to 2.66%, whereas having two older brothers would increase the probability to 3.53% (for further discussion, see Blanchard, 2001).…”