demonstrate that childhood gender nonconformity (CGN) is either the proximate ... evidence of a correlation between Childhood Gender Non-Conformity (CGN).
Biology and Philosophy 14: 505–519, 1999. © 1999 Kluwer Academic Publishers. Printed in the Netherlands.
Measuring Gender CHRISTOPHER D. HORVATH Departments of Philosophy and Biological Sciences Illinois State University Normal, Illinois USA
Abstract. Over the past several years, various operational definitions of gender have been used in studies of gender conformity in homosexual males. The goal of these studies is to demonstrate that childhood gender nonconformity (CGN) is either the proximate cause of adult homosexuality or an intermediate step in a biologically mediated process. The hypothesis of a causal connection between the development of gender and sexual orientation is embedded within the context of a biological (evolutionary) understanding of human behavior. Thus, testing the hypothesis of a causal connection between CGN and sexuality requires a concept of gender that is compatible with the basic principles of biological causation and our current understanding of evolutionary processes. I will argue that the concepts of gender used in the attempt to demonstrate a causal connection between CGN and sexual orientation are inappropriate because they provide no uniform, consistent method for identifying and measuring the biologically significant components of gender. I will also argue that the concept of gender that does emerge from these studies suggests an hypothesis about the connection between sexuality and gender that is not consistent with the cross-gendered theory of the etiology of homosexuality.
Introduction Recent behavioral genetic research clearly demonstrates a heritable biological component of sexual orientation in at least some homosexual males (Bailey and Pillard 1991; Hamer et al. 1993; Bailey et al. 1993). There is also strong evidence of a correlation between Childhood Gender Non-Conformity (CGN) and adult homosexuality in a substantial number of gay men (for review see Bailey and Zucker 1995). These findings have lead some evolutionary psychologists and behavioral geneticists to hypothesize a causal connection between the development of gender identity and sexual orientation in at least some homosexual males (Bem 1996; Blanchard and Klassen 1997; Green 1987; LeVay 1996; Blanchard 1997). The idea that homosexuals are cross-gendered (“sex-atypical” to use LeVay’s terminology (1996)) is obviously nothing new. In fact, the concept of homosexuals as cross-gendered is not only the prevailing stereotype, it is
506 also historically fundamental to the scientific study of homosexuality. Karl Heinrich Ulrichs (1825–1895), arguably, the first “out of the closet” gay man and the “father” of the modern gay rights movement, conceived of homosexuals as a distinct class of people differentiated from heterosexuals in that they possessed the bodies of their biological (genital) sex, but the minds of the opposite sex. Influenced by Ulrich’s ideas, Magnus Hirschfeld (1868– 1935), the founder of the modern scientific study of human sexuality, also believed that homosexuals were cross-gendered, but being a scientist and a good materialist, he put his hypothesis in terms of concrete brain structures and not just minds. Hirschfeld hypothesized that all human embryos possess “rudimentary neural centers” directing sexual attraction to both males and females (Hirschfeld 1896). In heterosexuals, the center for attraction to the opposite sex develops while the center for same-sex attraction regresses. In homosexuals, Hirschfeld argued, the opposite developmental sequence occurs. Exactly one hundred years later, the cross-gendered conception of homosexuality coupled with other correlational data about homosexual people motivates much of the current theorizing about the etiology of homosexuality (LeVay 1996). For example, two recent studies demonstrate that differences in the neuroanatomy of sexually dimorphic regions of the brain correlate with homosexuality in men (Allen and Gorski 1992; LeVay 1991). Simon LeVay, perhaps the country’s best known expert on sex and the brain, has published two books and countless newspaper columns promoting the idea that prenatal underexposure or overexposure to fetal androgens cause gay men’s brains to be “feminized” and lesbian brains to be “masculinized”. This sex-atypical development results in a more feminine gender and sexual attraction to males in gay men and a more masculine gender and sexual orientation toward females in lesbians (LeVay 1993, 1996). In men, sexual orientation is also highly correlated with the number of older brothers in the gay man’s family. Each additional older brother increases the odds of homosexuality by approximately 33% (Blanchard and Bogaert 1996). Blanchard and his colleagues have hypothesized that: this fraternal birth order effect reflects the progressive immunization of some mothers to Y-linked minor histocompatibility antigens (H-Y antigen) by each succeeding male fetus, and the concomitantly increasing effects of H-Y antibodies on the sexual differentiation of the brain in each succeeding male fetus. (Blanchard and Klassen 1997, p. 375) Despite the long history of the cross-gendered conception of homosexuality and its importance as a driving force behind much of the current research on the etiology of sexuality, the pattern of gender development in homosexuals and the ways in which the genders of homosexual adults vary from those
507 of same-sex heterosexual adults are still not well understood (Bailey et al. 1997). Up to this point, I have been using the terms “sex”, “gender”, and “sexual orientation” rather vaguely. In order to test the hypothesis that the development of gender and sexual orientation are causally connected, one must first have a way of systematically identifying and measuring both sexual orientation and gender. In the interest of clarity I will introduce some provisional definitions of “gender” and “sex” based in our common sense understanding of these terms. “Gender” is usually thought of as the set of behaviors, attitudes, and personality features as well as the dispositions to have the behaviors, attitudes, and personality features typical of males or of females. Of course, this definition also implies a dichotomous division into two sex categories – male and female. As we shall see, in the real world things are a bit more complex. Urlichs defined a person’s sex by the type of genitals they had. The advent of sex re-assignment surgery and the increased visibility of “intersexed” people has made categorizing people in this way problematic. How would you classify a person who’s genitals look “female” but are the functional and developmental equivalent of “male” genitals (i.e. an intersexed condition known as “Micropenis”)? Modern biologists and sex researchers classify people into sexes based on their sex chromosomes; XX individuals are female and XY individuals are male. This classification scheme is also problematic. Other combinations of sex chromosomes occur regularly in humans (e.g. XYY and XXX). There are also people who are XX but have “male” genitals and vice versa. In order to test our hypothesis, we will have to replace these vague, common sense concepts with more operational concepts. The scientific community engaged in the study of sexuality seems to have reached consensus on the Kinsey Scale as the way to identify and quantify sexual orientation (Kinsey, Pomeroy and Martin 1948). However, there is no single operational test of gender used consistently in psychosexual or evolutionary psychological research. In fact, the aspects of behavior and physiology that researchers treat as markers of “gender” differ greatly from study to study and from scientist to scientist. Evolutionary psychologists have identified several sexually differentiated behavioral and psychological traits and have provided us with adaptive explanations for them (see Buss and Schmitt (1993) and Symons (1979) for review). Examples of such evolved gender differences include males having a higher interest in causal sex, a heightened response to visual sexual stimuli, and a greater preference for youthful sexual partners. To put it simply, masculinity is the set of psychological and behavioral traits that conferred reproductive success of our male evolutionary ancestors. Femininity can be
508 understood in a similar way, it is the set of psychological and behavior traits that conferred reproductive success on our female ancestors. In the paper that follows, I will examine the concepts of gender used in several studies of gender conformity and homosexuality to make two points. First, I will argue that the concepts of gender used in the attempt to demonstrate a causal connection between CGN and sexual orientation are inappropriate because they provide no uniform, consistent method for identifying and measuring the biologically significant components of gender. Second, I will argue that what data we do have on the gender traits of homosexual adults suggest that homosexuals are not “cross-gendered” with respect to the sexually differentiated traits evolutionary psychologists understand best. In other words, the cross-gendered model of homosexuality is not consistent with our evolutionary understanding of gender.
Disclaimers A couple of caveats are in order. Number one: The brevity of my treatment of the Kinsey scale and studies of the biological basis of homosexuality should not be taken to suggest that they are unproblematic. The current hoopla around the “Biology of Homosexuality” is based on only three or four recently published papers (Bailey and Pillard 1991; Hamer et al. 1993; LeVay 1991). There is other work that has not yet made it into canon on this subject (e.g. Allen and Gorski 1992; Pattatucci and Hamer 1995; Swaab and Hofman 1990), but a great deal more research is clearly warranted. There are also several significant challenges to the biological account of homosexuality that must be answered. For example, the model for the development of homosexuality being discussed in this paper assumes that the regions of the brain that regulate sexual behavior in rodents and other mammals participate in the regulation of sexual orientation in humans. William Byne (1995) and Anne Fausto-Sterling (1995) have both provided persuasive arguments against this assumption. Instead of focusing here on the very real debate over the biology of homosexuality, I have chosen to concentrate on the difficulties presented by attempts to operationalize gender in a way that would allow one to draw causal connections between CGN and sexual orientation. The logic of my argument is that even if we accept (for the sake of argument) that homosexuality has a biological cause roughly like that proposed by the sex-atypical model, the hypothesis that the development of sexual orientation is causally linked to the development of gender through biological processes remains incoherent until we have a biologically adequate concept of gender.
509 Caveat number two: The very possibility of a biological theory of gender has been fiercely debated. Social constructionist and feminist critics argue that gender and sexual orientation are both the products of principally social processes – not biological ones. My relative silence on the debate between those who hold biological theories about gender and homosexuality and those who hold constructionist/feminist theories does not imply that this debate should be ignored. Rather, that debate is simply not the subject of this paper. Again, this paper is not about the merits of the biological theory relative to social constructivist or feminist alternatives, but about problems internal to the biological account itself. Those interested in an excellent articulation of the social constructionist argument should read Tiefer 1987. Anne FaustoSterling’s book Myths of Gender (1985) contains one of the classic feminist arguments against biological determinist accounts of gender. Caveat number three: As for the hypothesis that CGN is causally linked to sexuality by biological processes – I remain agnostic. The scientific debate over alternative models for the development of sexual orientation has not yet been adequately resolved. In addition, there are also non-biological theories that seek to explain the apparent correlation between CGN and adult homosexuality. The most recently proposed and widely discussed such theory is Deryl Bem’s “Exotic Becomes Erotic” theory (Bem 1996). According to Bem, childhood gender non-conformity (or conformity) may be the result of biological factors like genes or neuroanatomy. However, the causal connection between CGN and sexual orientation is not a biological one. Instead, a child’s degree of gender conformity causes them to feel “different” from opposite or same-sex peers. These feeling of difference produce “nonspecific autonomic arousal” that is then eroticized. In this way, one’s dissimilar peers become the objects of one’s erotic attraction. My point here is not to determine which theory is better, the biological or the psychological. My point is to demonstrate that the conceptions of gender currently in use within the biological model render the hypothesis biologically incoherent and to suggest a systemic understanding of sexuality and gender that makes the hypothesis testable from within an evolutionary framework. Finally, caveat number four: Most of the data collected about gender and sexual orientation has been collected on males. Any number of reasons have been cited for the obvious male-bias in this research: males are more likely to volunteer for research on sexuality and gender than females; gay men are more accessible at Pride Rallies and bars than lesbians; boys who behave in gender non-conformist ways are more easily identified than girls who do so; etc. What all of these reasons demonstrate is the pervasiveness of cultural
510 values surrounding sexuality and gender and the strength with which these values affect all research on gender and sexual orientation. The evolutionary framework While Hirschfeld was not explicitly an evolutionist, the modern hypothesis of a causal connection between the development of gender and sexual orientation is embedded within the context of an evolutionary understanding of human behavior (see for example LeVay 1996). The assumptions that underlie this hypothesis conceive of sexuality and gender as produced, at least in part, by processes whose ultimate causal explanation lies in our evolutionary past. The minimum requirement for an account of the evolutionary origin of any trait is that the theory begin with the identification of some heritable variation in that trait. Gender is not, however, a simple trait like eye color or blood type. Gender is a complex trait composed of a collection of behavioral and personality features differentially associated with a particular sex. The trait of “general intelligence”, while not sexually dimorphic, is in many ways analogous. Recent molecular genetic and heritability studies suggest a significant heritable influence throughout a person’s life on four key components of intelligence: general cognitive ability, verbal ability, spatial ability, and memory (McClearn et al. 1997). The hypothesis of a heritable causal link between gender and sexual orientation would require similar heritable influences on key components of gender (and sexual orientation). According to the hypothesis at issue, gender and sexual orientation are causally linked either in series or as effects of a common cause within a biologically based developmental system. In order for this system to have been produced by the process of evolution, both gender and sexual orientation must have a significant heritable component. In order to test the hypothesis that variations in the gender and/or sexual orientation system are heritable, one must be able to consistently identify and quantify the variations in that trait. One must be able to consistently quantify variations in these traits between individuals, between individuals of different generations, between individuals in different populations, and if you are trying to draw conclusions about evolutionary history, then between individuals in different species (i.e. homology). I have purposely not stipulated that these variations in gender and sexual orientation be tied to differences in fitness. While several people have argued that homosexuality is adaptive (e.g. Ruse 1982; Weinrich 1987), this is not the only alternative. For example, variations in sexual orientation may be the byproduct of the normal functioning of some other adaptive trait (or traits) completely unrelated to sexual behavior (e.g. the immune response
511 in Blanchard 1997). Providing an evolutionary account of the origin and development of sexual orientation does not require giving an adaptationist account (for additional alternatives to Adaptationism see Gould and Lewontin (1979)). Thus, while fitness differences associated with variations in sexual orientation and gender may have played a significant role in the ultimate evolutionary explanation, they are not necessary for such an account.
Operational concept of sexual orientation The Kinsey Scale (Kinsey, Pomeroy and Martin 1948) has become the standard way to operationalize sexual orientation in almost all scientific studies of the phenomenon. Each adult participant in such studies is asked a series of questions about their sexual desires, sexual behaviors, sexual fantasies, and sexual self-identity. Based on the answers given to these questions, the participant’s sexual orientation is classified somewhere along a unidimensional linear scale where 0 = exclusively heterosexual, and 6 = exclusively homosexual.
Homosexuality and gender role/identity Unfortunately, no such consensus exists around how to identify and quantify the complex trait of gender. In the studies under discussion here, participants’ gender was assessed either retrospectively or concurrently using questionnaires focused on three particular aspects of gender: The first is what Kohlberg (1966) termed gender identity – the ability to discriminate accurately between males and females and to accurately identify one’s own sex. The second, larger area of investigation involves what some call the gender role – the set of behaviors, attitudes, and personality features that are more typical of a male or female within a given society (Zucker 1985). Occupational interests, interest in fashion, domesticity, toy preference, and preference for same-sex or opposite-sex playmates are all examples of gender components of this type. The third subset of gender traits includes the erotic aspects of gender (Bailey, Kim and Hills 1996). For example, study participants were asked about their preference for particular sexual behaviors where insertive or aggressive behaviors were coded as masculine. Participants were also asked about preferences regarding the gender of their partners (i.e. do masculine gay men prefer feminine male partners) While there are some parallels between the various aspects of sexual orientation and aspects of gender, for example sexual self-identity and gender identity, and sexual behavior and gender role, there is no equivalent to the
512
Figure 1.
Kinsey Scale for gender. A review of the literature (Lippa and Connelly 1990) suggests that there have been at least three distinct approaches to the assessment of gender. Early tests were developed on a model that assumed masculinity and femininity were opposite poles on a unidimensional continuum analogous to the unidimensional linear scale Kinsey derived for sexual orientation (Terman and Miles 1936; Constantinople 1973) (Figure 1 top). In the 1970’s, the work of Spence and Helmreich (Spence, Helmreich and Stapp 1974) and of Bem (1974) suggested an alternative two-factor theory in which masculinity and femininity varied along two independent axis (Figure 1 bottom). Whatever the strengths of the two-factor theory of gender, the measures developed from it, the Bem Sex Role Inventory (BSRI) and the Personal Attributes Questionnaire (PAQ), proved to be very problematic (Pedhazur and Tetenbaum 1979). For example, males and females did not score significantly differently on the two subscales. In addition, scores on the subscales did not correlate highly with subject’s self-ratings of their own masculinity or femininity. Consideration of these problems led Spence to argue that the twofactor measures reveal gender as a construct made up of “many more or less independent factors” (Spence 1984). Early in childhood, most people develop a firm, unarticulated sense of “gender identity”. Men typically label their sense of maleness as “masculinity” and women label their sense of femaleness as “femininity”. However, the particular combinations and degree of the attributes, interests, attitudes, behaviors, etc. manifested may vary substantially between people with equally strong, unambiguous gender identities.
513
Figure 2.
In other words, these gender-typical phenomena are multidimensional and multifactorial. The multidimensional model of gender composes the third and most recent approach to the study of masculinity-femininity (Figure 2). Additional work on the results of the two-factor measures shows that factor analysis of the BSRI tends to yield at least four orthogonal factors (Blanchard-Fields and Suhrer-Roussel 1994). There are a great many aspects of human behavior that appear sexually dimorphic. Most of these characters are not assessed by either of the two factor measures still in use today. Any or all of these sexually dimorphic characters might well form other components of gender. Determining the actual structure of gender on the multidimensional model will require studying the covariation among attributes, interests, attitudes, behaviors, etc. that seem to show sex differences. A potentially confusing aspect of the current multidimensional model of gender is a return to a unidimensional concept of masculinity-femininity (Lippa and Connelly 1990). A simultaneous appreciation of both the multidimensionality of gender and the unidimensionality of masculinityfemininity is possible if one conceives of the latter as a trait whose indicators include some, but not all traits that show sex differences. For example, occupational interests, sexual orientation, mental rotation ability, interests in casual sex, and height are all traits that show moderate to high degrees of sexual differentiation and so may all be components of gender. However,
514 it is reasonable to suspect that, at least in contemporary Western societies, judgments about an individual’s masculinity-femininity, by either the individual him or herself or an outside observer, would be much more strongly associated with his/her occupational interests and sexual orientation than with any of the other traits. The concept of gender that emerges from contemporary studies of sexual differentiation is that of a complex, multidimensional, multifactorial trait. Some of the individual factors that comprise gender may be unidimensional like masculinity-femininity, and others may themselves be multidimensional. Some gender traits may be biologically based and heritable – mental rotations ability for example. Other components of gender are far less likely to be based in biology or to be heritable in a way that makes them candidates for evolutionary explanations – for example, interest in certain occupations or in fashion. How then do we make sense of the cross-gendered causal theory of homosexuality? There is a strong correlation between Childhood Gender Nonconformity and adult homosexuality (Green 1987; Zuger 1988). One set of prospective studies indicates that in boys who display a high degree of CGN, 75% will go on to become gay men (Bailey and Zucker 1995). But, as we have seen, gender is a complex of related, but independent, sex-differentiated traits. Are children who are identified as “Gender-Nonconformist” nonconformist with respect to the majority of the traits that make up gender, or with respect to those components of gender that have a strong basis in hormones and neurobiology, or to those traits that play an important adaptive role? Reviews of the literature (Bailey and Zucker 1995) show that the aspects of CGN most highly correlated with homosexuality include: a preference for opposite-sex playmates, sex-atypical interest in athletics (less interest for boys, more for girls), interest in clothing of the opposite sex, an expressed desire to be the opposite sex, sex-atypical career interests, and a social reputation as a “sissy” or a “tomboy”. This is a fairly heterogeneous list of characteristics and the CGN hypothesis suggests two alternatives with respects to these traits. The first alternative is that early biological (hormonal) factors may act on the brains of homosexual individuals in utero to make them similar to opposite sex individuals with respect to neuroanatomical structures that affect both sexual orientation and the traits listed above (common cause). There is as of yet no reasonably explicit neuropsychological theory that links brain structures to all of these traits or to homosexuality. There is evidence that some of these traits may be affected by neurohormonal interactions – Girls with congenital adrenal hyperplasia are more interested in stereotypically boys’ toys than in stereotypically girls’ toys (Berenbaum and Snyder 1995; Berenbaum and Hines
515 1992) and they are more likely to report homosexual feelings than unaffected girls (Dittmann, Kappes and Kappes 1992). However, at the same time, these studies report that early exposure to androgens do not have an effect on playmate preference (Berenbaum and Snyder 1995). The second alternative suggested by the CGN hypothesis is that early exposure to some biological factors (again probably hormones) causes the development of the gender nonconformist traits which in turn through a developmental system as yet unknown, causes the child to develop the sexual orientation more typical of the opposite sex. Several scientists have suggested this as the most likely scenario (Bem 1996; Fagot, Leinbach and Hagan 1986; Kohlberg 1966). Of course, it may be that sexual orientation develops first, and that homosexual orientation causes some children to develop sex-atypical gender characteristics. It is unlikely that all of the CGN characteristics have a causal basis in hormones or neuroanatomy, or that they are heritable in the way necessary for an evolutionary explanation. Before a causal link can be drawn between CGN and adult homosexuality within a biological model, researchers will need to specify which aspects of gender non-conformity are in fact most strongly correlated with homosexuality. If the strongest connection exist between the non-biologically mediated factors, then a significant hormonal causal link would seem doubtful. In any event, the etiology of homosexuality is likely to be complex and involve both neuroedocrinological and purely social factors. Closer attention to the multidimensionality of gender identity is necessary to help elucidate this complex phenomenon. Given the strength of the correlation between CGN and homosexuality at least in some gay men, it would be reasonable to expect some sex-atypicallity to persist into adulthood. The cross-gendered model of homosexuality that motivates the CGN hypothesis strongly implies that adult homosexuals have some sex-atypical gender traits. Stereotypes associate gay men with “feminine” occupations (hairdresser, interior decorator, dancer) and lesbians with masculine occupations (athlete, truck driver, soldier). Gay men are stereotypically interested in cooking, shopping for antiques, and fashion while lesbians play sports, shop for hardware, and are conspicuously uninterested in fashion. Finally, gay men and lesbians are stereotypically sex-atypical in their appearance and mannerisms. While the degree to which these stereotypes are true on average has not been well studied, what data does exist suggests that there is considerable variability in sex-typed behavior among adult gay men and lesbians (Bailey et al. 1997). Although homosexual and heterosexual people report large average differences in their childhood behavior, a substantial portion of homosexual adults do not recall much childhood gender nonconformity at all (Bailey and
516 Zucker 1995). Mother’s memories of their gay son’s childhood sex-typed behavior seem to corroborate these individual differences (Bailey, Nothnagel and Wolfe 1995). Perhaps, as some scientists have plausibly suggested, there are multiple etiologies for homosexuality only one (or some) of which are associated with CGN (Meyer-Bahlburg 1993). If the cross-gendered model of homosexuality is to stand as a valid conception within a biological framework of at least some sexual orientation, then there should be some biologically significant sex-atypical traits manifested by at least those homosexuals with the relevant etiology. The ways in which and the degree to which homosexual adults are sex-atypical have not been extensively investigated. However, if one takes the biologically significant components of gender to be those that evolutionary psychologists argue serve significant evolutionary (adaptive) roles, then there is some data at least about gay men. Evolutionary psychologists have argued that male’s interest in causal sex, their interest in visual sexual stimuli along with an emphasis on partner’s appearance, and their preference for younger sexual partners all show strong sexual differentiation and all serve important adaptive functions (Buss and Schmitt 1993). Research done by Michael Bailey and colleagues (Bailey et al. 1997; Bailey, Kim and Hills 1996) shows that there is a significant difference between males and females in interest in casual sex, but that gay and straight men are on average equally interested in it. Their work also demonstrates that there is no significant difference between heterosexual and homosexual men in the importance they place on their partner’s appearance or their response to visual sexual stimuli. Work done on the age of partner preferences also indicates no appreciable difference between heterosexual and homosexual males (Kenrick et al. 1995). There are however, two sexually dimorphic, adaptively significant behavioral traits on which homosexual and heterosexual men do differ. On studies of aggressiveness and of sexual jealously, homosexual males are more similar to heterosexual females than to heterosexual males (Bailey, Kim and Hills 1996).
Conclusion What does all of this data demonstrate about the cross-gendered conception of homosexuality and the hypothesis that CGN is causally linked to homosexuality? If the multidimensional model of gender is correct, then to say that homosexuals possess the bodies of one sex, but the gender of the other is relatively meaningless. In order to test the cross-gendered causal theory of homosexuality, one must investigate which particular aspects of the multi-
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