home
billy jack
homophobia
a gay gene?
the bible
cultural context
discussion
a 'gay gene?'assault on gay america

Is Homosexuality Inherited?  by Richard Horton


Richard Horton is the editor of The Lancet, the British medical journal.
I.

Historians of homosexuality will judge much twentieth-century "science" harshly when they come to reflect on the prejudice, myth, and downright dishonesty that litter modern academic research on sexuality. Take, for example, the lugubrious statements of-once respected investigators. Here is Sandor Feldman, a well-known psychotherapist, in 1956:

It is the consensus of many contemporary psychoanalytic workers that permanent homosexuals, like all perverts, are neurotics.[1]

Or consider the remarks of the respected criminologist Herbert Hendin:

Homosexuality, crime, and drug and alcohol abuse appear to be barometers of social stress... Criminals help produce other criminals, drug abusers other drug abusers, and homosexuals other homosexuals.[2]

The notion of the homosexual as a deeply disturbed deviant in need of treatment was the orthodoxy until only recently. Bernard Oliver, Jr., a psychiatrist specializing in sexual medicine, wrote in 1967 that Dr. Edmond Bergler feels that the homosexual's real enemy is not so much his perversion but [sic] ignorance of the possibility that he can be helped, plus his psychic masochism which leads him to shun treatment....

There is good reason to believe now, more than ever before, that many homosexuals can be successfully treated by psychotherapy, and we should encourage homosexuals to seek this help.[3]

Such views about the origin of homosexual preferences have become part of American political culture as well. When, in 1992, Vice-President Dan Quayle offered the view that homosexuality "is more of a choice than a biological situation.... It is a wrong choice,"[4] he merely reasserted the belief that homosexuality reflected psychological conditioning with little biological basis, and certainly without being influenced by a person's biological inheritance.

And now we have the much publicized spectacle--Time magazine has taken up the story in a dramatic feature entitled "Search for a Gay Gene"[5] --of homosexuality's origins being revealed in the lowly fruit fly, Drosophila.[6] Males and females of this, one has to admit, rather distant relation adopt courtship behavior that has led two researchers at the US National Institutes of Health to draw extravagant parallels with human beings.

Shang-Ding Zhang and Ward F. Odenwald found that what they took to be homosexual behavior among male fruit flies--touching male partners with forelegs, licking their genitalia, and curling their bodies to allow genital contact--could be induced by techniques that abnormally activated a gene called w (for "white," so called because of its effect on eye color). Widespread activation (or "expression") of the white gene in Drosophila produced male-to-male rituals that took place in chains or circles of five or more flies. If female fruit flies lurked nearby, male flies would only rarely be tempted away from their male companions. These findings, which have apparently been reproduced by others, have led the investigators to conclude that "w misexpression has a profound effect on male sexual behavior."

Zhang and Odenwald go on to speculate that the expression of w could lead to severe shortages of serotonin, an important chemical signal that enables nerve cells to communicate with one another. The authors conjecture that mass activation of w diminishes brain serotonin by promoting its use elsewhere in the body. Indeed, cats, rabbits, and rats all show some elements of "gay" behavior when their brain serotonin concentrations fall. Intriguing and, you might think, convincing evidence.

Yet, although w is found in modified form in human beings, it is a huge (and, it seems to me, a dangerous) leap to extrapolate observations from fruit flies to humans. In truth, when the recent data are interpreted literally we find that (a) the w gene induces male group sex behavior in highly ritualized linear or circular configurations, and (b) while these tend more toward homosexual than straight preferences, they are truly bisexual (as pointed out by Larry Thompson in Time). Zhang and Odenwald force their experimental results with fruit flies to fit their preconceived notions of homosexuality. How simplistic it seems to equate genital licking in Drosophila with complex individual and social homosexual behavior patterns in humans. Can notions of homosexuality apply uniformly across the biological gulf that divides human beings and insects? Such arguments by analogy seem hopelessly inadequate.

By contrast, the work of Simon LeVay, Dean Hamer, and a small group of researchers concerned to distinguish biological and genetic influences on sexual behavior has discredited much of the loose rhetoric that has been used about homosexuality. In August 1991, LeVay, a neuroscientist who now directs the Institute of Gay and Lesbian Education in southern California, published in the magazine Science findings from autopsies of men and women of known sexual preference. He found that a tiny region in the center of the brain--the interstitial nucleus of the anterior hypothalamus (INAH) 3--was, on average, substantially smaller in nineteen gay men who died from AIDS than among sixteen heterosexual men.[7]

The observation that the male brain could take two different forms, depending on one's sexual preference, was a stunning discovery. The hypothalamus-a small, intricate mass of cells lying at the base of the brain-was long believed to have a role in sexual behavior, but direct evidence that it did so was weak. Yet LeVay expressed caution. Although his data showed that human sexual preference "is amenable to study at the biological level," he noted that it was impossible to be certain whether the anatomical differences between the brains of gay and straight men were a cause or a consequence of their preference.[8]

In the thirteen persuasive essays that make up The Sexual Brain, LeVay takes account of the current bio-behavioral controversy over the science of sex. From the union of wiry sperm and bloated ovum to the child-rearing practices of mammals and humans, for which mothers are largely responsible, he writes (metaphorically), the "male is little more than a parasite who takes advantage of [the female's] dedication to reproduction." He goes on to draw from a wide range of sources to support his contentious assertion that "there are separate centers within the hypothalamus for the generation of male-typical and female-typical sexual behavior and feelings." He argues that a connection--the details of which remain mysterious--between brain and behavior exists through hormones such as testosterone.

The most convincing evidence he puts forward to support his view comes from women with congenital adrenal hyperplasia. This condition, in which masculine characteristics, such as androgenized genitalia, including clitoral enlargement and partially fused labia, become pronounced in women, is caused by excessive testosterone production and leads, in adulthood, to an increased frequency of lesbianism affecting up to half of all the women who have the condition. The theory, still unproven, that is proposed to explain these behavioral effects of hormones is that one or more chemical signals act during a brief early critical period in the development of most males to alter permanently both the brain and the pattern of their later adult behavior. Unless this hormonal influence is switched on, a female pattern of development will follow automatically.

What might be the origin of biological differences underlying male sexual preference? In 1993 Dean Hamer and his colleagues at the National Cancer Institute discovered a preliminary but nevertheless tantalizing clue.[9] Hamer began his painstaking search for a genetic contribution to sexual behavior by studying the rates of homosexuality among male relatives of seventy-six known gay men. He found that the incidence of homosexual preference in these family members was strikingly higher (13.5 percent) than the rate of homosexuality among the whole sample (2 percent). When he looked at the patterns of sexual orientation among these families, he discovered more gay relatives on the maternal side. Homosexuality seemed, at least, to be passed from generation to generation through women.

Maternal inheritance could be explained if there was a gene influencing sexual orientation on the X chromosome, one of the two human sex chromosomes that bear genes determining the sex of offspring.[10] Men have both X and Y chromosomes, while women have two X chromosomes. A male sex-determining gene, called SRY, is found on the Y chromosome. Indeed, the Y chromosome is the most obvious site for defining male sexuality since it is the only one of the forty-six human chromosomes to be found in men alone. The SRY gene is the most likely candidate both to turn on a gene that prevents female development and to trigger testosterone production. Since the female has no Y chromosome, she lacks this masculinizing gene. In forty pairs of homosexual brothers, Hamer and his team looked for associations between the DNA on the X chromosome and the homosexual trait. They found that thirty-three pairs of brothers shared the same five X chromosomal DNA "markers," or genetic signatures, at a region near the end of the long arm of the X chromosome designated Xq28.[11] The possibility that this observation could have occurred by chance was only 1 in 10,000.

LeVay takes a broad philosophical perspective in his discussion of human sexuality by placing his research in the context of animal evolution. Hamer, on the other hand, has written, with the assistance of the journalist Peter Copeland, a more focused popular account of his research. He conceived his project after reflecting on a decade of laborious research on yeast genes. Although the project was approved by the National Institutes of Health after navigating a labyrinthine course through government agencies, it remained rather meagerly funded.

Taken together, the scientific papers of both LeVay and Hamer and the books that their first reports have now spawned[12] make a forceful but by no means definitive case for the view that biological and genetic influences have an important--perhaps even decisive--part in determining sexual preference among males. LeVay writes, for example, that "...the scientific evidence presently available points to a strong influence of nature, and only a modest influence of nurture." But there is no broad scientific agreement on these findings. They have become mired in a quasi-scientific debate that threatens to let obscurantism triumph over inquiry. What happened?

To begin with, we must ask what LeVay and Hamer have not shown. LeVay has found no proof of any direct link between the size of INAH 3 and sexual behavior. Size differences alone prove nothing. He was also unable to exclude the possibility that AIDS has an influence on brain structure, although this seemed unlikely, since six of the heterosexual men he studied also had AIDS. Moreover, Hamer did not find a gene for homosexuality; what he discovered was data suggesting some influence of one or more genes on one particular type of sexual preference in one group of people. Seven pairs of brothers did not have the Xq28 genetic marker, yet these brothers were all gay. Xq28 is clearly not a sine qua non for homosexuality; it is neither a necessary nor a sufficient cause by itself.

And what about women? Although the genitalia of women as well as men are clearly biologically determined, no data exist to prove a genetic link, or a link based on brain structure, with female sexual preferences, whether heterosexual or homosexual. Finally, neither study has been replicated by other researchers, the necessary standard of scientific proof. Indeed, there is every reason to suppose that the INAH 3 data will be extremely difficult to confirm. Only a few years ago INAH 1 (located close to INAH 3) was also thought to be larger in men than in women. Two groups, including LeVay's, have failed to reproduce this result.

Most of these limitations are clearly acknowledged by both LeVay and Hamer in their original scientific papers and are reinforced at length in their books. But reactions to their findings have nevertheless been harshly critical. For instance, after pointing out several potential weaknesses in Hamer's study and criticizing his decision to publish in Science at a time when gay "lives are at stake," two biologists, Anne Fausto-Sterling and Evan Balaban, asked "whether it might not have been prudent for the authors and the editors of Science to have waited until more of the holes in the study had been plugged...."[13] Fortunately, their somewhat hysterical reaction has been followed by more careful comment by other scientists.[14]

Lack of prudence also characterized the response in the press. In London, the conservative Daily Telegraph ran the clumsy headline, "Claim that homosexuality is inherited prompts fears that science could be used to eradicate it." Another story began, "A lot of mothers are going to feel guilty," while another was entitled "Genetic tyranny."

These headlines are part of the popular rhetoric about DNA, which supposes that a gene represents an irreducible and immutable unit of the human self. The correlation between a potentially active gene and a behavior pattern is assumed to indicate cause and effect. Was Hamer himself guilty of over-interpretation? In his original paper, he went to extraordinary lengths to qualify his findings. He and his co-authors offer no fewer than ten statements advising a cautious reading of their data, and they note that "replication and confirmation of our results are essential." Neither the hyperbolic press response with its relentless message of genetic determinism nor the ill-judged scientific criticism was appropriate.

Nevertheless, there are three conceptual issues raised by these reports --namely, heritability, sexual categorization, and the meaning of the phrase "biological basis of behavior" --which have been largely ignored in the scramble to publish instant analyses of the findings of LeVay and Hamer, among others.

2.

Heritability is a measure of the resemblance between relatives; it is expressed as the proportion of variability in an observable characteristic that can be attributed to genetic factors. Eye color, for example, is 100 percent heritable, whereas we know that most behavioral traits have genetic contributions of well below 50 percent. Heritability is a quarrelsome issue among geneticists, and its proportional value is often quoted without the necessary qualifications. Variation in any trait is accounted for by the influence of genes (including, importantly, the interaction among genes), environment (the family and one's wider life experience), and the interaction between one or more genes and one or more environmental variables. The standard measure of heritability is the sum of all genetic influences, and it ignores potentially complex interactions--for example, the influence of the family milieu on the behavioral expression of a gene influencing sexual preference. The most common error made by those who discuss genetic contributions to behavior is to forget that heritability is a property only of the population under study at one particular time. It cannot be generalized to characterize the behavior itself.

When we apply these considerations to Hamer's data, we make a surprising discovery. If we accept his own hypothesis of the relation between the Xq28 marker and the behavioral trait, the maximum heritability of homosexuality in the group he studied is 67 percent, which may seem a remarkably high figure. Yet this group was a particularly selected one: the seventy-six study participants openly acknowledged being gay, and had volunteered for the study. What Hamer's results do not tell us is what the influence of the Xq28 marker in the general population might be. He infers from various mathematical calculations "that Xq28 plays some role in about 5 to 30 percent of gay men." But he admits that this is merely a preliminary estimate and that accurate measuring of Xq28 heritability in the general population remains to be done. In fact, a frequent criticism of Hamer's Science paper was that he did not measure the incidence of Xq28 markers among heterosexual brothers of gay sibling pairs. Without this information, it is impossible to guess the influence of any genes that might be located at Xq28. Their effects will be unpredictable at best, and any interaction with the environment will assume critical importance.

At this point, science inches uneasily toward dogma and diatribe. Hamer cites Richard Lewontin's Not in Our Genes[15] as one of his early inspirations to change the direction of his research. Hamer writes that he

knew that [Lewontin] had criticized the idea that behavior is genetic, arguing instead that it is a product of class-based social structures....Why was Lewontin, a formidable geneticist, so determined not to believe that behavior could be inherited? He couldn't disprove the genetics of behavior in a lab, so he wrote a political polemic against it.

Indeed, Lewontin has frequently provided cogent arguments against the view that heritability can help delineate the effects of genes on human behavior.[16] He has described the separation of behavioral variation into genetic and environmental contributions and the interaction between the two as "illusory."[17] For him and his co-writers, such a model "cannot produce information about causes of phenotypic difference," i.e., differences in observable physical and mental traits. The precise meaning of heritability forces the inevitable conclusion, Lewontin has written, that whatever proportion is quoted, it "is nearly equivalent to no information at all for any serious problem in human genetics."

Imagine Dean Hamer's astonishment, therefore, when he received a letter from Richard Lewontin in 1992. A Harvard professor teaching genetics and behavior had invited Hamer to submit a pamphlet describing his research as an example of "conceptual advances" in "modern behavior genetic studies." He had willingly complied, but only later discovered that it had been ruled "scientifically unacceptable" by Ruth Hubbard, an emeritus professor at the Harvard Biological Laboratories deeply skeptical about determinism. In his letter, Hamer writes, Lewontin

went on to theorize that human behaviors must be "very, very far from the genes" because "there are some at least that we know for sure are not influenced by genes as, for example, the particular language one speaks." That made about as much sense as saying that since some people eat tacos and some eat hamburgers, there is no biological drive to eat.

Hamer, tongue firmly in cheek, offered to give Lewontin's students a lecture on how good research into behavior genetics is done. Lewontin accepted. On the day of his scheduled talk, Hamer faced not only Lewontin but also Ruth Hubbard and Evan Balaban (a co-author of the hostile letter later published in Science). Hamer described his methods carefully and stressed that his research could identify only potential genetic influences and not isolate specific genetic causes of behavior. At the end of the lecture, Lewontin indicated that he had no dispute with Hamer after all, and left the classroom without further comment. One wonders from this if Lewontin has modified his views on studying genetic contributions to human behavior.

Although it is true that heritability is only a crude measure of genetic influence, it remains a valuable research tool if, as one scientist has said, the researchers realize that

genetic influence on behavior appears to involve multiple genes rather than one or two major genes, and nongenetic sources of variance are at least as important as genetic factors....This should not be interpreted to mean that genes do not affect human behavior; it only demonstrates that genetic influence on behavior is not due to major-gene effects.[18]

More importantly, one can move beyond the "lump sum" theory of genetic influences to study the way in which genes affect behavior over time, or to discover how a gene influences different but possibly related behaviors, for instance both sexual preference and aggression.

Lewontin also cited the "terrible mischief" that could result from a research program based on heritability as his reason to suggest stopping "the endless search for better methods of estimating useless quantities."" Hamer agrees that precise genetic determinacy is an impossible goal; his 1993 article for Science on DNA markers also ended with an unusual admonition:

We believe that it would be fundamentally unethical to use [this] information to try to assess or alter a person's current or future sexual orientation, either heterosexual or homosexual, or other normal attributes of human behavior. Rather, scientists, educators, policy-makers, and the public should work together to ensure that such research is used to benefit all members of society.

If scientists who have opposed research on heritability would accept that it can have, when it is carried out in this spirit, an important place in the study of behavior, that would add much-needed weight to calls to expand, and improve, research on human sexuality.

Although Hamer and LeVay have both expressed cautious confidence in their results, they are evidently uneasy about their own categorizations of men as either gay or straight. Hamer writes that,

In truth, I don't think that there is such a thing as "the" rate of homosexuality in the population at large. It all depends on the definition, how it's measured, and who is measured.

Classifying sexuality into homosexual and heterosexual categories may have benefits of simplicity for researchers, but how closely does this division fit the real world? Poorly is the answer. Sexual behavior and styles of life among men and women vary from day to day and year to year, and a conclusion about whether or not sexual experience is characterized as homosexual frequently depends on the definition one uses.[20] The slippery nature of our crude categories should alert us to beware of conclusions about groups labeled as "homosexual" or "heterosexual."

Moreover, the concept of sexuality itself cannot easily be analyzed. It exists at several levels--chromosomal, genital, brain, preference, gender self-image, gender role, and a range of subtle influences on behavior (hair color, eye color, and many more). Each of these can be grouped together with the others to produce a single measurable component on a scale, devised by Alfred Kinsey in the 1940s, that allegedly shows a person's degree of homosexual preference. Hamer used this scale somewhat uncritically to categorize his volunteers. Stephen Levine, a medical expert on sexual behavior, has noted that the conflated and crude Kinsey scale "does not do justice to the diversity among homosexual women and men."[21]

One of Hamer's severest critics, Anne Fausto-Sterling, a developmental geneticist at Brown University, has tried to extend sexual categories beyond the binary divisions of male and female[(22] She suggests adding three more groups based on "intersex" humans: herms (true hermaphrodites who possess one testis and one ovary), merms (individuals who have testes, no ovaries, but some female genitalia), and ferms (who have ovaries, no testes, but some male characteristics). This attempt to create multiple categories is, however, futile. It tries to systematize the un-systematizable by proposing a neatly divided-up continuum of sexuality, while, in fact, very different and mutually exclusive factors may be at work in particular cases. It is an impossible and intellectually misguided task.

Two major studies examining the historical origins of modern sexual categories show how social groupings that evolve over time can mislead one into supposing that inherent biological classes exist in some unchangeable sense. Michel Foucault chronicled the history of sexual norms by concentrating on the fluid notion of "homosexuality."[23] He denounced what he called "Freud's conformism" in taking heterosexuality to be the normal standard in psychoanalysis. He concluded:

We must not forget that the psychological, psychiatric, medical category of homosexuality was constituted from the moment it was characterized--Westphal's famous article of 1870 on "contrary sexual sensations" can stand as its date of birth[24]--less by a type of sexual relations than by a certain quality of sexual sensibility.... The sodomite had been a temporary aberration; the homosexual was now a species.

This analysis, it seems to me, points to a critical error in the research of both Hamer and LeVay. Both, in spite of their qualifications, adopt the idea of the homosexual as a physical "species" different from the heterosexual. But there are no convincing historical grounds for this view. As Foucault points out, at the time of Plato,

People did not have the notion of two distinct appetites allotted to different individuals or at odds with each other in the same soul; rather, they saw two ways of enjoying one's pleasure...

The cultural historian Jonathan Katz has recently attacked the naive partitioning of sexual orientation by tracing the dominance of the norm--heterosexuality --throughout history.[25] He provides a convincing argument that the "just-is hypothesis" of heterosexuality--i.e., that the word corresponds to a true behavioral norm--is an "invented tradition." He shows that the categories of gay and straight are gradually dissolving as notions of the family become more various. Basing his view more on intuition than on sociological evidence, he predicts "the declining significance of sexual orientation."

The final issue that has confused the interpretation of research into sexuality is the meaning of "biological influence." Unfortunately, both LeVay and Hamer, in their effort to popularize their findings, ignore the subtlety of this question. As has been noted, LeVay is unambiguous about his own position on biological determinism,

The most promising area for exploration is the identification of genes that influence sexual behavior and the study of when, where, and how these genes exert their effects.

Both researchers ignore the central issue in the debate over nature and nurture. The question is: How do genes get you from a biochemical program that instructs cells to make proteins to an unpredictable interplay of behavioral impulses--fantasy, courtship, arousal, sexual selection--that constitutes "sexuality"? The question remains unresolved. The classic fall-back position is to claim that genes merely provide a basis, at most a predisposition, to a particular behavior. But such statements lack a precise or testable meaning.

Perhaps we are asking the wrong question when we set out to find whether there is a gene for sexual orientation. We know that genes are responsible for the development of our lungs, larynx, mouth, and the speech areas of our brain. And we understand that this complexity cannot be collapsed into the notion of a gene for "talking." Similarly, what possible basis can there be for concluding that there is a single gene for sexuality, even though we accept that there are genes that direct the development of our penises, vaginas, and brains? This analogy is not to deny the importance of genes, but merely to recast their role in a different conceptual setting, one devoid of dualist prejudice.

The search for a single dominant gene--the "O-GOD" (one gene, one disorder) hypothesis--that would influence a behavioral variant is likely to be fruitless. Many different genes, together with many different environmental factors, will interact in unpredictable ways to guide behavioral preferences. Each component will contribute small quanta of influence. One result of such a quantum theory of behavior is that it makes irrelevant the overstretched speculations of both Hamer and LeVay about why a gene for homosexuality still exists when it apparently has little apparent survival value in evolutionary terms. The quest for a teleological explanation to identify a reason for the existence of a "gay gene" becomes pointless when one understands that there is not now, and never was, a single and final reason for being gay or straight, or having any other identity along the continuum of sexual preference.

3.

Does this complexity, together with an adverse and polarized social milieu, preclude successful research efforts concerning human sexuality? In 1974, Lewontin wrote that reconstruction of man's genetic past is "an activity of leisure rather than of necessity."[26] Perhaps so. But, as Robert Plomin argues, the value of studying inheritance in behavior lies in its importance

per se rather than in its usefulness for revealing how genes work. Some of society's most pressing problems, such as drug abuse, mental illness, and mental retardation, are behavioral problems. Behavior is also a key in health as well as illness, in abilities as well as disabilities, and in the personal pluses of life, such as sense of well-being and the ability to love and work.[27]

What research into human sexuality, then, lies ahead? Dean Hamer has repeated his initial work among male homosexuals in an entirely new group of families and has included a much-needed analysis of women. He has also compared the frequency of the Xq28 marker among pairs of gay siblings and their heterosexual brothers, important control data that he did not acquire the first time around. This work has been submitted to the journal Nature Genetics. Two other teams--one recently formed at the National Institutes of Health and a Canadian group that has reached some preliminary results--are attempting to replicate Hamer's initial findings. All Hamer will say about his latest data is that they have not discouraged him from continuing with his project.

To track down and sequence the DNA from one or more relevant genes at Xq28, from a total of about two hundred candidates, seems an almost insuperable task. To read the molecular script of DNA involves deciphering millions of constituent elements. Moreover, each gene will have to be studied individually and many more pairs of gay brothers will be needed to achieve this goal. The work will be extremely difficult for a single laboratory to undertake on its own. Hamer's request for a federally funded center for research into sexuality--a National Institute of Sexual Health--is therefore timely, for the study of differences between the sexes has reached a critical, though admittedly fragmented, stage and a coordinated research program would be valuable.

The concerns of such an institute should be broad. For example, it might have included the recent work reported from Yale which overturns the conventional view that language function is identical for both men and women.[28] By studying which brain areas were activated during various linguistic tasks, the Yale scientists found that women used regions in both their right and left brain cortices in certain instances, while men used only the left side of their brains. If functional brain differences for sophisticated behaviors exist between the sexes, the task for the future would be to link function to structure and to describe how both evolve from a background of genetic and environmental influence.

Inevitably, the idea of biological determinism carries with it the threat of manipulating the genes or the brain in order to adapt to the prevailing norm. As I have noted, Hamer was acutely aware of this possibility when he wrote his paper. But the prospects for pinpointing genetic risk have moved rapidly and worryingly forward with the recent availability of genetic screening techniques for, among other diseases, several cancers, including a small proportion of cancers of the breast, colon, and thyroid. Most such techniques are used without any current prospect for gene therapy or for any other effective treatment of the conditions identified. Geneticists such as Francis Collins, director of the Human Genome Project, have opposed unrestricted and unregulated screening techniques, describing their recent uses as "alarming"[29] because we are "treading into a territory which the genetics community has felt rather strongly is still [in the stage of] research." Hamer's fine words opposing genetic manipulation are likely to mean little in the marketplace if his work eventually leads to the isolation of a gene that has an effect on sexual preference, even if it has only a small effect that is present in only a limited number of people. US state legislatures are slowly responding to these issues. Colorado recently became the eleventh state to enact a law preventing information derived from genetic testing to be used in a discriminatory fashion.

In recognition of the emerging risks from dubious applications of preliminary discoveries, NIH launched a Task Force on Genetic Testing in April. The twenty-member committee includes representatives from industry, managed-care organizations, and patient-advocacy groups, and is chaired by Neil A. Holtzman, a professor of pediatrics and health policy at Johns Hopkins University. Far from being a friend to the hyperbolists, Holtzman has written that "physicians should be at the forefront of decrying florid genetic determinism and its dire implications for health and welfare reform."[30] His committee is charged with performing a two-year study of genetic technologies, which will look specifically at the accuracy, safety, reliability, and social implications of new testing procedures. This move is not without self-interest on the part of the geneticists at the NIH. Members of the US Congressional House Appropriations Committee, which closely monitors NIH spending, have said that they may freeze the Human Genome Project's $153 million grant if ethics issues are not given close attention.

But sex-based research has already run into political trouble. The Council for Citizens Against Government Waste has charged that some NIMH research is a misuse of taxpayer's money. Tom Schatz, CCAGW's president, has criticized twenty such studies, including one involving research into sex offenders. Rex Cowdry, acting director of the National Institute of Mental Health, argues that "for these grants, I think first you have to believe that the factors that motivate and control sexual behavior are worth knowing about...you have to believe that knowing more about how men and women are both similar and different is important."[31]

With such partisan pressures dominating the future of the research agenda, the circulation of uninformed opinions couched in scholarly prose is a cause for anxiety. In an otherwise superb and iconoclastic critique of the history of heterosexuality, Jonathan Katz ends with a sweeping and badly informed declaration:

Biological determinism is misconceived intellectually, as well as politically loathsome...Contrary to today's bio-belief, the heterosexual/homosexual binary is not in nature, but is socially constructed, therefore deconstructable.

LeVay and Hamer on the one hand, and Katz, on the other, evidently have taken completely antithetical positions. But Katz's extreme intellectual reductionism makes him as guilty as the more simplistic biologists and journalists who inflate claims about every new genetic discovery. After convincingly undermining the distinction between gay and straight, he then accepts the naive dualism of nature vs. nurture. It is such attempts as Katz's to put into opposition forces that are not in opposition which argue so strongly for planned research free from the ideological temptations that he succumbs to. Biological research into sexuality will indeed be misconceived if we assume that we already understand the differences between the sexes. In part the results of that research often contradict any such assumption. Katz demands that "we need to look less to oracles [presumably biological], and trust more in our desires, visions, and political organizing." But to take this path risks perpetuating a debate based on ignorance rather than one based on evidence.

It is true that the research of Hamer and LeVay presents technical and conceptual difficulties and that their preliminary findings obviously need replication or refutation. Yet their work represents a genuine epistemological break away from the past's rigid and withered conceptions of sexual preference. The pursuit of understanding about the origins of human sexuality --the quest to find an answer to the question, What does it mean to be gay and/or straight?--offers the possibility of eliminating what can be the most oppressive of cultural forces, the prejudiced social norm.

FOOTNOTES

1 See Perversions: Psychodynamics and Therapy, edited by Sandor Lorand and Michael Balint (Ortolan Press, 1965; first edition, Random House, 1956), p. 75.

2 Quoted in Kenneth Lewes, The Psychoanalytic Theory of Male Homosexuality (Simon and Schuster, 1988), p. 188.

3 See Bernard J. Oliver, Jr., Sexual Deviation in American Society (College and University Press, 1967), p. 146.

4 See Karen de Witt, "Quayle Contends Homosexuality Is a Matter of Choice, Not Biology," The New York Times, September 14, 1992, p. A17.

5 See Larry Thompson, "Search for a Gay Gene," Time (June 12, 1995), pp. 60-61.

6 See Shang-Ding Zhang and Ward F. Odenwald, "Misexpression of the White (w) Gene Triggers Male-male Courtship in Drosophila," Proceedings of the National Academy of Sciences, USA, Vol. 92 (June 6, 1995), pp. 5525-5529.

7 See Simon LeVay, "A Difference in Hypothalamic Structure Between Heterosexual and Homosexual Men," Science (August 30, 1991), pp. 1034-1037.

8 The suprachiasmatic nucleus, also located in the hypothalamus, is larger in homosexual men than in either heterosexual men or women. The anterior commissure of the corpus callosum (a band of tissue that connects the right and left hemispheres of the brain) is also larger in gay men.

9 See Dean H. Hamer et al., "A Linkage Between DNA Markers on the X Chromosome and Male Sexual Orientation," Science (July 16, 1993), pp. 321-327.

10. The normal complement of human chromosomes is forty-six per individual, two of which are designated sex chromosomes. In the male, the sex chromosomal makeup is XY, while in the female it is XX. If a gene for homosexuality (Xh) was transmitted through the maternal line, one can see how the subsequent offspring would be affected.

(Chart omitted)

Suppose the unaffected female carrier for homosexuality (XXh) produced offspring with a non-Xh male (XY). Half of all female children would be carriers of Xh (like their mothers), while half of all male offspring would carry Xh unopposed by another X. The Xh trait -- homosexuality -- would then be able to express itself.

11 By chance, one would expect each pair of brothers to share half their DNA. So, assuming that there was no gene for homosexuality, one would expect twenty of the forty pairs of brothers to share the X chromosome marker.

12 LeVay has recently completed a second book in collaboration with Elisabeth Nonas--City of Friends--that surveys gay and lesbian culture; it will be published by MIT Press in November. He is currently working on Queer Science, a study of how scientific research has affected the lives of gays and lesbians.

13 See Anne Fausto-Sterling and Evan Balaban, "Genetics and Male Sexual Orientation," Science (September 3, 1993), p. 1257.

14 For example, see David Weatherall, Science and the Quiet Art (Norton, 1995) who notes that "these findings should not surprise us. Almost every condition...reveals a complex mixture of nature and nurture," p. 287.

15 See R.C. Lewontin, S. Rose, and L. J. Kamin, Not in Our Genes (Pantheon, 1984).

16 Lewontin is not a total skeptic about the importance of molecular genetics research in medicine. For instance, he accepts "that some fraction of cancers arise on a background of genetic predisposition." See R.C. Lewontin, "The Dream of the Human Genome," The New York Review (May 28, 1992), pp. 31-40.

17 See M. W. Feldman and R. C. Lewontin, "The Heritability Hang-up," Science (December 19, 1975), pp. 1163-1168.

18 See Robert Plomin, "The Role of Inheritance in Behavior," Science (April 13, 1990), pp. 183-188.

19 See R.C. Lewontin, "The Analysis of Variance and the Analysis of Causes," The American Journal of Human Genetics, Vol. 26 (1974), pp. 400-411.

20 For example, in a UK study (see Anne M. Johnson, "Sexual lifestyles and HIV risks," Nature [December 3, 1992], pp. 410-412), although only 1.4 percent of men reported a male partner during the past five years, 6.1 percent of men reported having experienced some same-gender behavior.

21 See Stephen B Levine, Sexual Life: A Clinician's Guide (Plenum, 1992). The Kinsey scale has seven levels ranging from exclusively heterosexual (0) to exclusively gay (6). Hamer applied this scale to four aspects of sexuality: self-identification, attraction, fantasy, and behavior.

22 See Anne Fausto-Sterling, "The Five Sexes: Why Male and Female Are Not Enough," The Sciences (March/April, 1993), pp. 20-24.

23 See Michel Foucault, The History of Sexuality, Vols. One and Two (Vintage, 1990).

24 Dr. K.F.O. Westphal became the first modern author to publish an account of what he described as a "contrary sexual feeling" (Die contrare Sexualempfindung), although the word homosexual was first used in a private letter written by Karl Maria Kertbeny on May 6, 1868. This linguistic history is described in detail by Jonathan Katz (see note 25).

25 See Jonathan Ned Katz, The Invention of Heterosexuality (Dutton, 1995).

26 R.C. Lewontin, "The Analysis of Variance and the Analysis of Causes," The American Journal of Human Genetics, Vol. 26 (1974), pp. 400-411.

27. Robert Plomin, "The Role of Inheritance in Behavior," Science (April 13, 1990), pp. 183-188.

28. See Bennett A. Shaywitz et al., "Sex differences in the functional organization of the brain for language," Nature (February 16, 1995), pp. 607-609.

29 See Gina Kolata, "Tests to Assess Risks for Cancer Raising Questions," The New York Times (March 27, 1995), p. A1.

30 See Neil A. Holtzman, "Genetics," Journal of the American Medical Association (April 26, 1995), pp. 1304-1306.

31 See "NIMH's Cowdry Defends Institute's Research Against Appropriations Committee, Watchdog Group Criticism," The Blue Sheet (March 29, 1995), pp. 5-6.

This article originally appeared in the New York Review of Books, (July, 1995).

Reproduced with permission of the copyright owner. Further reproduction or distribution is prohibited without permission. Copyright ©1995 New York Review of Books. All rights reserved.



home · billy jack ·  homophobia's roots ·  a gay gene? ·  the bible's words ·  cultural context
discussion ·  quiz ·  viewer's guide
press ·  tapes & transcripts ·  synopsis ·  FRONTLINE

web site copyright 1995-2014 WGBH educational foundation

SUPPORT PROVIDED BY

NEXT ON FRONTLINE

The Rise of ISISOctober 28th

FRONTLINE on

ShopPBS