Debates and research on homosexuality are complex, at times paradoxical, and seldom uncontroversial. Conflicting arguments about the origins of homosexuality abound, with much of the confusion stemming from contradictory definitions of the term “homosexual” used by researchers. Indeed, the operational definition of sexual orientation is an ongoing problem in the field of sex research (Kauth, 2005). A specific dilemma in the research on homosexuality is that, invariably, researchers have excluded instances of same-sex behavior not associated with an exclusively or predominantly homosexual orientation or identity (Muscarella, 1999). However, as Muscarella (2006) affirms, “a valid examination of homosexuality must include all of its manifestations” (p. 277). The assumption that all humans can be neatly categorized as heterosexual and reproductive, or homosexual and nonreproductive, is not supported by the evidence (Kauth, 2002; Kirkpatrick 2000). Knowing this, I will refrain from essentializing human sexuality as an either/or, gay/straight, binaristic phenomenon and include in this paper research on both homosexual orientation and behavior, with a greater focus on behavior. Additionally, in order to address the complexity and diversity of human sexuality, I will include studies and research that are cross-cultural and cross-historical in scope.
The aim of this paper is to explicate the evidence from two major views regarding homosexuality. One side, comprised mostly of North American researchers and Western subject pools, posits that homosexuality is a relatively rare biological aberration, whereas the other side, incorporating cross-cultural and historical research, argues that homosexuality is, in reality, a widespread and evolutionarily adaptive phenomenon. Those who posit homosexuality as biologically determined and relatively infrequent point to studies that suggest homosexuality (specifically same-sex behavior and orientation) occurs rarely, is the result of atypical brain and hormonal variations, and likely stems from genetic causes. Conversely, those arguing that homosexuality is widespread and evolutionarily adaptive cite studies that suggest same-sex sexuality is common, albeit undercover, throughout human societies, and provide evidence showing that the dichotomous “homosexual/deviant” versus “heterosexual/normative” view of sexuality is a relatively recent social construct specific to Western societies. Moreover, this side argues that both male-male and female-female sexual behaviors are evolutionarily adaptive in that they solidify same-sex alliances, which has advantages for group survival.
Researchers studying the biological origins of homosexuality argue that it is a biologically based anomaly, pointing to evidence suggesting that homosexuality occurs rarely in the general population. Indeed, a number of North American studies have suggested that homosexuals are rare in comparison to heterosexuals. For example, a US study in which five probability surveys were conducted between 1970 and 1990 shows that only about five to seven percent of men report some same-gender sexual contact during adulthood (Rogers & Turner, 1991). Additional support for the argument that homosexuality is rare in comparison to heterosexuality was provided by the US National Health and Social Science Survey (1994). Researchers in this study estimated that the prevalence of homosexuality among American males is approximately 2 percent (Laumann, Gagnon, Michael, & Michaels, 1994). Additionally, Statistics Canada, as part of its 2003 Canadian Community Health Survey, revealed that, out of 135,000 respondents aged 18-59, only 1.3% of men and 0.7% of women reported being homosexual (Statistics Canada, 2004). It must be noted, however, that these surveys reveal the percentages only of people willing to admit to certain behaviors or sexual orientations (Cronin, 1993). Surveys like these fail to distinguish between homosexual behavior, identity, and orientation, and omit people who hesitate to reveal their sexuality because of social stigma or repression of their sexual feelings (Rathus, Nevid, Fichner-Rathus, Herold, & McKenzie, 2007).
There is some evidence that genetics may play a role in sexual orientation. For instance, in a recent study, Kirk, Bailey, & Martin (2000) performed research on pairs of twins in which at least one member identified himself as homosexual. They found that about 52% of monozygotic twin pairs were concordant for a homosexual orientation, contrasted with 22% of dizygotic twins and only 11% of adoptive twin brothers. This study suggests that a homosexual orientation is partly influenced by genetics. However, the development of a homosexual orientation “appears to be strongly influenced by non-genetic factors,” and its occurrence cannot be reliably predicted in individuals (Muscarella, 2006: p. 278).
Recent findings suggest that the development of a homosexual orientation involves atypical neurohormonal differentiation of the brain (Rahman & Wilson, 2003). More specifically, it has been argued that a likely cause of homosexuality is the pattern of exposure of the developing brain to sex hormones (Carlson et al., 2005: p. 430). For instance, some experiments have shown that if a female rat is subjected to stress during pregnancy, the pattern of secretion of sex hormones is altered, and the sexual development of the offspring is affected (Anderson, Fleming, Rhees, & Kinghorn, 1986). However, in a lecture on October 14th, 2008, to a Psychology of Gender 320 class, Professor A. Coury broached the fact that it is highly problematic to generalize results from rats to human beings, especially regarding sexual behavior, as the physiology, psychology, and overall brain structure of rats are highly dissimilar to people.
More support for the hypothesis that homosexuality is caused by exposure to hormones comes from the work of Simon LeVay (1991). In his study, LeVay dissected the brains of deceased heterosexual and homosexual males and found differences in the size of two different subregions of the hypothalamus and in a bundle of axons that connects the right and left temporal lobes. It cannot be concluded that any of these regions are involved in people’s sexual orientations (Kimmel, 2008). However, the results do suggest that the brains may have been exposed to different patterns of hormones prenatally (LeVay, 1991; Carlson et al., 2005).
Several striking problems exist in LeVay’s methodology and so I feel must be mentioned. First of all, LeVay was not able to confirm whether the heterosexual men in his sample were, in fact, completely heterosexual. Also, all of the homosexual men in his sample had died of AIDS (a disease known to affect the brain), and thus their brains were preserved in a formaldehyde solution that was of a different strength than the solution in which the brains of the purportedly heterosexual men were preserved. After reading the study, I could find no evidence of effort to control for the effect of the formaldehyde on the organs. Thus, I would agree with Kimmel’s (2008) observation that “it is possible that what LeVay may have been measuring was the combined effect of HIV infection and preservation in high densities of formaldehyde solution on postmortem brain structure, rather than differences in brain structure between living heterosexuals and homosexuals” (p. 37). It also must be noted that recent efforts to replicate LeVay’s findings have failed (Kimmel, 2008).
Those who argue that homosexuality is a widespread and evolutionarily adaptive phenomenon observe that cultures around the world, both Eastern and Western, have embraced homo- and bi-sexual relations. In fact, homosexuality is found everywhere measurement is possible and has existed throughout human history “in most, perhaps all, human cultures” (Henrich, 2008; Kirkpatrick, 2000; p. 385). In their review of the literature on 76 preliterate societies, Ford & Beach (1951) found homosexuality to be normative and deemed socially acceptable in 49 (64%) of societies. In the other 27 societies (36%), same-sex behavior actively persisted even in the face of social sanctions against it. In societies where it is not taboo, homosexual behavior is common and used to build relationships between members of the same sex (Muscarella, 2006). Proponents of this view argue that the widespread occurrence of homosexual behavior means that we should not refer to it as “unnatural” or as a rare genetic aberration (Carlson, Buskist, Enzle, & Heth, 2005: p. 429).
A small sampling of the many cultures possessing some form of socially entrenched homosexuality and bisexuality include classical Greece (Fone, 2000; Crompton, 2003; Percy, 2005), the Sambia of New Guinea (Baldwin & Baldwin, 1989), numerous North American First Nations societies (before Western infiltration) (Weiringa, 1989), pre-Meiji Japan (Fone, 2000), and late imperial China (Crompton, 2003). Although it is problematic to compare animals to humans, it is interesting to note that bisexuality is the norm for bonobos and chimpanzees, who happen to be the closest primate relatives to humans (bonobos share 99.4 per cent of their genetic makeup with humans) and is also common throughout the animal kingdom. In his book Biological Exuberance: Animal Homosexuality & Natural Diversity, Bruce Bagemihl (1999) outlines 450 of over 15,000 species that have been observed engaging in homosexual and bisexual behavior. He also discusses how, until recently, zoologists invariably neglected to document animal homosexuality. This observation points to just how repressed discourse on homosexuality has been in Western cultures.
Proponents of the view that homosexuality is widespread broach the surprising finding that the majority of people who engage in homosexual behavior identify as heterosexual. Certainly, regarding sexual identity (as opposed to actual sexual behavior), the number of people in Western cultures who describe themselves as exclusively homosexual exceeds the number who describe themselves as bisexual (Carlson et al., 2005: p. 430). However, with reference to human sexual behavior, the data strongly show that bisexual behavior is more common than homosexual behavior (Kirkpatrick, 2000). In fact, as Kirkpatrick has discussed, most individuals who engage in homosexual behavior are, in practice, bisexual (e.g. Melanesia [Herdt, 1984], classical Athens [Dover, 1989], contemporary United States [Kinsey, Pomeroy, & Martin, 1948, Kinsey et al., 1953]). Additionally, the historical record suggests that most same-sex sexual behavior among humans has been exhibited by those who are not exclusively homosexual (Muscarella, 2006). For instance, literary and biographical sources as well as recovered court records for sodomy accusations suggest that the majority of men in 17th-century Japan and 15th-century Florence may have been bisexual (Schalow, 1989; Leupp 1995; Rocke, 1996). In the indigenous communities of North America (prior to Western infiltration), the majority of those engaging in homosexual sex were gender-typical individuals “who were clearly bisexual” (Callender & Kochems, 1983: p. 443). In his work The Evolution of Homosexual Behavior, Kirkpatrick (2000) goes on to observe that the same is true for numerous preliterate societies such as those in Tahiti (e.g. Herdt, 1997).
A number of studies provide support for the notion that far more people experience homosexual attraction than who actually act on this attraction. This could be due to social stigmas surrounding homosexuality in Western societies (Henrich, 2008). In an Australian study that surveyed medical students, for instance, it was found that most homosexual attraction is felt by those whose behavior is predominately or exclusively heterosexual (McConaghy, Buhrich, & Silove, 1994).
Kinsey, Pomeroy, & Martin’s (1948; 1953) findings support the notion that human sexual orientation is not cut and dry. Stressing the variations between exclusive heterosexual and exclusive homosexual behavior and feeling, Kinsey denied that human beings “represent two discrete populations, heterosexual and homosexual” (Kinsey et al., 1948). For example, nearly half of his male sample admitted to having erotic responses to members of both sexes during their adult lives, with 37 per cent admitting to having sexual experiences with other males that lead to orgasm (Kinsey et al., 1948). Some academics and conservative groups argue that Kinsey’s data are skewed because his sample was comprised of only those who were willing to discuss taboo topics (Gathorne-Hardy, 2004). Despite this criticism, it is hard to dispute that the findings reveal sexuality as something far more fluid and porous than previously imagined by Western researchers. Cross-historical comparisons also lay stake to this claim.
Societal ideals of sexual identity and behavior have changed over time, which leads one to question the popular view of sexual identity as a stable and ahistorical signifier. For instance, Foucault (1978) has discussed how the homosexual/heterosexual identity dichotomy is in fact a Western notion that came into existence in the 1860s. Connell (2005) discusses how “the late 19th century was a time when ‘the homosexual’ as a social type became clearly defined… At earlier periods of history, sodomy had been officially seen as an act which might be undertaken by any [emphasis mine] person who gave way to evil. Homosexual desire was now viewed as defining a particular type of person, the ‘invert’ in the most common medical view” (196). According to the theorizing of Adriaens & De Block (2006), cultural responses to same-sex sexuality led to the spread of exclusive homosexual behavior and to the creation of a homosexual identity. In other words, homosexuality went from being an impulse or act that anyone was capable of engaging in to an identity held by a visible, stigmatized minority. As Katz (1995) observes, the creation and entrenchment of the heterosexual (normal) and homosexual (deviant) identity categories serves to “affirm the superiority of heterosexuals over homosexuals” (p. 112).
Unlike in most Western cultures, so-called “gay” behavior is common or even expected in other societies, problematizing the notion that homosexuality is a rare genetic anomaly. Aboriginal cultures, for instance, challenge Western notions of sexuality through their non-binaristic view of gender and sexuality (Wieringa, 1989). In her work on North American Aboriginal history, Tafoya (1997) discusses how “most [N]ative communities tend[ed] not to classify the world into the concrete binary categories of the Western world—good/bad, right/wrong, male/female, gay/straight—but rather into categories that range from appropriateness to inappropriateness, depending on the context of the situation” (2). In other words, Aboriginal concepts, including those pertaining to sexuality, tended to prefer circles to lines: “if one takes the line of a male/female, gay/straight, and bends it into a circle, there are an infinite number of points. Just so, there are theoretically an infinite number of possible points of gender and sexual identity for an individual that can shift and differ over time and location” (Tafoya, 1997: p. 8).
Another example of cross-cultural differences comes from Egypt and other Arab-Muslim countries, where the criteria for what makes a person homosexual is envisaged through a completely different paradigm than that of North American societies (Gamson, 2004). Whitaker observes that in Egypt, “if a man assumes the active role in anal intercourse with another man, his action is not…regarded as shameful or as indicating sexual orientation. …The fact that he [has sexual intercourse with] with a man rather than a woman may even be interpreted as a sign of heightened manhood” (2006: p. 206). The idea of extending same-sex activity beyond physical satisfaction into an exclusive homosexual practice and orientation is considered a completely Western notion in most Arab countries, where homosexual behavior (rather than identity) is common.
As Massad (2002) affirms, while homosexual behavior is prevalent throughout the Middle East, there is no word for ‘homosexual’ in the Arab language; the concept of homosexual identity is completely foreign and seen as a recent Western ideological import. For many Saudis, for instance, the fact that a man has sex with another man has little to do with “gayness.” The act may fulfill a desire or a need, but it does not constitute an identity. Nor does it strip a man of his masculinity, as long as he is in the “top,” or active, role in the same-sex encounter (Labi, 2007).
Present-day Western societies tend to view homosexuality as completely oppositional to heterosexuality. In other words, a widely held view about human sexuality is that people are either “gay” or “straight.” As Kauth (2005) observes, “that classification of sexual orientation is almost exclusively linked to sex of the actors in contemporary Western culture and scientific theory is an artifact of our culture” (p. 35). The ancient Greeks, for example, would have been “perplexed by the idea that one could judge a person by exclusive reference to the object of sexual desire, without reference to a particular sexual act, or that one could be a ‘homosexual’ or ‘a heterosexual’” (Fone, 2000: p. 26).
Much like the present-day norms surrounding homosexuality in Saudi Arabia and Egypt, the ancient Greeks attached more importance to the sexual instinct than to the sex object (Henderson, 1975). According to Fone (2000), what most concerned the Greek male was not whether the object of desire was male or female, but “what place that object occupied in the social and sexual hierarchy” (p. 26). As Foucault (1985) explains, “for the Greeks, it was the opposition between activity and passivity that was essential, pervading the domain of sexual behaviors and that of moral attitudes as well” (pp. 85-86). In other words, ancient Greek conceptualizations of masculinity included being the active partner in a sexual encounter; the sex of the partner being penetrated was largely irrelevant and had no influence on an individual’s identity (Foucault, 1978).
Incorporating findings that demonstrate the cross-cultural pervasiveness of homosexuality, a growing body of research in the field of evolutionary psychology suggests that homosexual behavior is an evolutionary adaptation. Henrich (2008) agrees that sexual desire evolved for reproductive purposes, but adds that in many species, including humans, sex also releases bonding hormones such as oxytocin. This bonding system (and humans’ “supersexuality”) can then be exploited to build and sustain same-sex relationships (such as dominance hierarchies) and alliances, which help individuals survive and subsequently reproduce (Psyc 358 lecture, 2008; Muscarella 2006; Kirkpatrick 2000; Vasey, 2006; Vasey, Pocock, & VanderLaan, 2007). This evolutionary view of human same-sex behavior is termed the alliance formation hypothesis, and is derived from evolutionary theories pertaining to reciprocal altruism.
The alliance formation hypothesis suggests that people’s sexual preferences are malleable, and, at least over the course of development, most individuals are capable of desiring same-sex sex. In other words, according to researchers working in the field of evolutionary psychology, the majority of human beings are capable of responding erotically to members of both sexes, using sex to affirm and re-affirm same-sex relationships (Adriaens & De Block, 2004; Kirkpatrick, 2000; Muscarella, 2006). In this view, humans, like other primates, are adapted to be bisexual (e.g. Vasey, 2006). Proponents of the alliance formation hypothesis argue that, with regard to genetic explanations for homosexuality, genes “matter” in Western societies. That is, Western society’s oppression of homosexuality may bring out the influence of genetic variation (Henrich, 2008).
Through my perusal of the research, I found that studies on female homosexuality were not as common as those on male homosexuality. However, as discussed in lecture, Diamond (2007) and Chivers, Seto, & Blanchard (2007) provide evidence that female sexuality also demonstrates emblematic features of a dynamical and evolutionarily adaptive system, including nonlinear change over time, spontaneous emergence of novel forms, and periodic reorganizations and phase transitions within the overall system (Diamond, 2007; Chivers, Seto, & Blanchard, 2007). Homosexual behavior appears to be used for the formulation and maintenance of same-sex alliances and dominance hierarchies in both males and females (Kirkpatrick, 2000).
I have demonstrated the cross-cultural diversity and fluidity of sexuality and thus have problematized claims of researchers who argue that homosexuality is rare and is determined solely by biological factors. Given the cross-cultural multiplicity of human sexual expression, it is not surprising that the single-factor “gay gene” theory of homosexuality has been criticized as overly simplistic and insufficient (Stein, 1999). Consequently, in my review of the literature, I join the consensus among the majority of sex researchers that “a homosexual orientation [identifying as gay] is the product of an interaction between genetic, cultural, developmental, and psychological factors” (Muscarella, 2006: p. 279). In the words of Kirkpatrick (2000), “within a basic bisexual potential, some individuals will fall at homosexual and heterosexual extremes” (p. 398).
In contrast with this biopsychosocial explanation for those with an exclusive homosexual orientation, I side with researchers who have demonstrated that homosexual behavior (concurrent with heterosexual behavior) is widespread, and that the degree to which homosexual behavior is exhibited in a population is largely determined by the norms of the culture in question. Indeed, cross-cultural evidence suggests that cultural norms and taboos have great influence on sexual behavior despite purported biological propensities. After all, were human sexual behavior completely or even predominately determined by biology, we would not find such broad plurality in cross-cultural and historical investigations of male and female homosexual behavior (Rathus et al., 2007). As Kinsey has observed, the wide occurrence of same-sex behavior in cultures where it is not taboo “suggests that the capacity of an individual to respond erotically to any sort of stimulus, whether it is provided by another person of the same or opposite sex, is basic in the species” (Kinsey et al., 1948; p. 660). The pervasiveness of homosexual behavior coupled with evidence suggesting that it aids in the formation same-sex bonds, which equates to advantages for group survival, makes it plausible that homosexual behavior is in fact an evolutionarily adaptive trait utilized throughout the course of human history.
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