Is Homosexuality Genetic? A Critical Review and Some Suggestions Mcguire Terry

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

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 instance, the lugubrious statements of-once respected investigators. Here is Sandor Feldman, a well-known psychotherapist, in 1956:

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

Or consider the remarks of the respected criminologist Herbert Hendin:

Homosexuality, crime, and drug and alcohol abuse appear to exist 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 demand of handling 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'due south real enemy is not and so much his perversion just [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 than e'er before, that many homosexuals can exist successfully treated past psychotherapy, and we should encourage homosexuals to seek this help.[3]

Such views nigh 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,"[iv] he merely reasserted the belief that homosexuality reflected psychological conditioning with little biological basis, and certainly without being influenced past a person'southward biological inheritance.

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

Shang-Ding Zhang and Ward F. Odenwald establish 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 result on eye colour). Widespread activation (or "expression") of the white gene in Drosophila produced male-to-male rituals that took identify in chains or circles of five or more flies. If female person fruit flies lurked nearby, male person flies would only rarely be tempted away from their male person companions. These findings, which have apparently been reproduced by others, take led the investigators to conclude that "w misexpression has a profound outcome on male sexual beliefs."

Zhang and Odenwald keep to speculate that the expression of w could lead to severe shortages of serotonin, an important chemic signal that enables nerve cells to communicate with one another. The authors conjecture that mass activation of w diminishes brain serotonin by promoting its utilize 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 lot might retrieve, convincing bear witness.

Withal, although w is found in modified form in human beings, it is a huge (and, it seems to me, a dangerous) spring to extrapolate observations from fruit flies to humans. In truth, when the recent information are interpreted literally we find that (a) the west factor induces male group sexual activity beliefs in highly ritualized linear or circular configurations, and (b) while these tend more toward homosexual than straight preferences, they are truly bisexual (every bit pointed out by Larry Thompson in Time). Zhang and Odenwald forcefulness 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. Tin can notions of homosexuality apply uniformly across the biological gulf that divides man beings and insects? Such arguments by illustration seem hopelessly inadequate.

Past contrast, the work of Simon LeVay, Dean Hamer, and a minor group of researchers concerned to distinguish biological and genetic influences on sexual behavior has discredited much of the loose rhetoric that has been used nearly homosexuality. In Baronial 1991, LeVay, a neuroscientist who at present directs the Institute of Gay and Lesbian Education in southern California, published in the magazine Scientific discipline 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 inductive hypothalamus (INAH) 3--was, on average, substantially smaller in nineteen gay men who died from AIDS than among xvi heterosexual men.[vii]

The observation that the male encephalon could take two different forms, depending on one's sexual preference, was a stunning discovery. The hypothalamus-a small-scale, intricate mass of cells lying at the base of the brain-was long believed to accept a part in sexual behavior, but direct evidence that it did and so was weak. Yet LeVay expressed caution. Although his data showed that human sexual preference "is acquiescent to report at the biological level," he noted that it was incommunicable 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 brand up The Sexual Brain, LeVay takes business relationship 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 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 "in that location are dissever centers inside the hypothalamus for the generation of male-typical and female-typical sexual behavior and feelings." He argues that a connexion--the details of which remain mysterious--between brain and behavior exists through hormones such every bit testosterone.

The nearly convincing evidence he puts forward to support his view comes from women with congenital adrenal hyperplasia. This condition, in which masculine characteristics, such equally androgenized ballocks, 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 upwardly to half of all the women who accept the condition. The theory, withal unproven, that is proposed to explain these behavioral effects of hormones is that one or more than chemical signals act during a brief early on critical period in the development of near males to change permanently both the encephalon and the blueprint of their after 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 Found discovered a preliminary but nonetheless tantalizing clue.[9] Hamer began his painstaking search for a genetic contribution to sexual behavior past studying the rates of homosexuality among male person relatives of 70-6 known gay men. He plant that the incidence of homosexual preference in these family unit 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 than gay relatives on the maternal side. Homosexuality seemed, at least, to be passed from generation to generation through women.

Maternal inheritance could exist explained if at that place was a gene influencing sexual orientation on the Ten chromosome, i of the ii human sex activity chromosomes that bear genes determining the sex of offspring.[10] Men take both 10 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 virtually obvious site for defining male sexuality since information technology is the but one of the forty-six human being chromosomes to be found in men solitary. The SRY gene is the near 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 xl pairs of homosexual brothers, Hamer and his team looked for associations betwixt the Deoxyribonucleic acid on the X chromosome and the homosexual trait. They found that xxx-three pairs of brothers shared the aforementioned v X chromosomal Deoxyribonucleic acid "markers," or genetic signatures, at a region most the terminate of the long arm of the X chromosome designated Xq28.[11] The possibility that this observation could have occurred past 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 development. Hamer, on the other hand, has written, with the assist of the journalist Peter Copeland, a more focused popular account of his research. He conceived his projection 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 regime agencies, information technology remained rather meagerly funded.

Taken together, the scientific papers of both LeVay and Hamer and the books that their kickoff reports have now spawned[12] make a forceful merely by no ways definitive case for the view that biological and genetic influences accept an important--possibly even decisive--function in determining sexual preference amidst males. LeVay writes, for example, that "...the scientific show presently available points to a strong influence of nature, and just a modest influence of nurture." Just there is no wide scientific understanding on these findings. They have become mired in a quasi-scientific contend that threatens to let obscurantism triumph over research. 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 beliefs. Size differences solitary prove nothing. He was also unable to exclude the possibility that AIDS has an influence on brain structure, although this seemed unlikely, since 6 of the heterosexual men he studied likewise had AIDS. Moreover, Hamer did non detect a factor for homosexuality; what he discovered was data suggesting some influence of one or more genes on one detail type of sexual preference in one group of people. Seven pairs of brothers did not take the Xq28 genetic marker, notwithstanding these brothers were all gay. Xq28 is clearly not a sine qua non for homosexuality; information technology is neither a necessary nor a sufficient crusade by itself.

And what about women? Although the ballocks of women as well as men are clearly biologically adamant, no data be to evidence 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 volition be extremely hard to confirm. Just a few years agone INAH ane (located close to INAH iii) was as well thought to exist larger in men than in women. Ii groups, including LeVay's, take 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 report and criticizing his determination to publish in Science at a time when gay "lives are at pale," two biologists, Anne Fausto-Sterling and Evan Balaban, asked "whether it might not accept been prudent for the authors and the editors of Scientific discipline to have waited until more of the holes in the report had been plugged...."[thirteen] 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 bourgeois Daily Telegraph ran the clumsy headline, "Claim that homosexuality is inherited prompts fears that scientific discipline could exist used to eradicate information technology." Another story began, "A lot of mothers are going to experience guilty," while some other 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 man 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 boggling lengths to qualify his findings. He and his co-authors offer no fewer than 10 statements advising a cautious reading of their data, and they notation that "replication and confirmation of our results are essential." Neither the hyperbolic printing 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.

Heritability is a measure of the resemblance betwixt relatives; information technology is expressed as the proportion of variability in an observable characteristic that tin can be attributed to genetic factors. Centre color, for example, is 100 percentage heritable, whereas we know that most behavioral traits accept genetic contributions of well beneath l percentage. Heritability is a quarrelsome issue amongst 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 amidst genes), environment (the family and one's wider life experience), and the interaction betwixt one or more than genes and ane or more environmental variables. The standard mensurate of heritability is the sum of all genetic influences, and it ignores potentially circuitous interactions--for example, the influence of the family unit milieu on the behavioral expression of a gene influencing sexual preference. The most common error made past those who discuss genetic contributions to behavior is to forget that heritability is a property only of the population nether written report at one particular time. It cannot be generalized to characterize the behavior itself.

When we apply these considerations to Hamer's data, nosotros make a surprising discovery. If we accept his ain hypothesis of the relation between the Xq28 mark and the behavioral trait, the maximum heritability of homosexuality in the grouping he studied is 67 per centum, which may seem a remarkably high figure. Yet this group was a particularly selected one: the seventy-six study participants openly acknowledged existence 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 part in about 5 to xxx percentage 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'due south Scientific discipline newspaper was that he did non measure out the incidence of Xq28 markers among heterosexual brothers of gay sibling pairs. Without this information, it is incommunicable to gauge the influence of any genes that might exist located at Xq28. Their effects volition be unpredictable at best, and whatever interaction with the environment will assume critical importance.

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

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

Indeed, Lewontin has often provided cogent arguments confronting the view that heritability can help delineate the effects of genes on man behavior.[16] He has described the separation of behavioral variation into genetic and ecology contributions and the interaction betwixt the two as "illusory."[17] For him and his co-writers, such a model "cannot produce information nigh causes of phenotypic departure," i.eastward., 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'south astonishment, therefore, when he received a alphabetic character from Richard Lewontin in 1992. A Harvard professor teaching genetics and behavior had invited Hamer to submit a pamphlet describing his enquiry as an case of "conceptual advances" in "modern beliefs 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 alphabetic character, Hamer writes, Lewontin

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

Hamer, tongue firmly in cheek, offered to give Lewontin's students a lecture on how good inquiry into behavior genetics is done. Lewontin accustomed. On the day of his scheduled talk, Hamer faced not only Lewontin merely also Ruth Hubbard and Evan Balaban (a co-author of the hostile letter later on published in Scientific discipline). Hamer described his methods advisedly 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 subsequently all, and left the classroom without further comment. One wonders from this if Lewontin has modified his views on studying genetic contributions to human being behavior.

Although it is true that heritability is simply a rough measure of genetic influence, it remains a valuable enquiry tool if, every bit one scientist has said, the researchers realize that

genetic influence on behavior appears to involve multiple genes rather than 1 or two major genes, and nongenetic sources of variance are at least as important as genetic factors....This should not be interpreted to hateful that genes exercise not affect human behavior; it only demonstrates that genetic influence on behavior is non due to major-gene effects.[18]

More than chiefly, one can move beyond the "lump sum" theory of genetic influences to written report the way in which genes touch behavior over time, or to discover how a gene influences different but peradventure related behaviors, for instance both sexual preference and assailment.

Lewontin also cited the "terrible mischief" that could result from a research programme based on heritability as his reason to propose stopping "the endless search for better methods of estimating useless quantities."" Hamer agrees that precise genetic determinacy is an impossible goal; his 1993 commodity for Scientific discipline 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 electric 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 enquiry is used to benefit all members of lodge.

If scientists who have opposed research on heritability would take that information technology can take, 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 better, inquiry on homo sexuality.

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

In truth, I don't recollect 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 existent world? Poorly is the answer. Sexual beliefs and styles of life among men and women vary from day to solar day and year to year, and a decision virtually whether or not sexual experience is characterized as homosexual often depends on the definition 1 uses.[xx] The glace nature of our rough categories should warning the states to beware of conclusions near groups labeled as "homosexual" or "heterosexual."

Moreover, the concept of sexuality itself cannot hands be analyzed. It exists at several levels--chromosomal, genital, brain, preference, gender self-image, gender role, and a range of subtle influences on beliefs (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 past Alfred Kinsey in the 1940s, that allegedly shows a person's caste 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 calibration "does not exercise justice to the diversity amongst homosexual women and men."[21]

Ane of Hamer'southward severest critics, Anne Fausto-Sterling, a developmental geneticist at Dark-brown University, has tried to extend sexual categories beyond the binary divisions of male person and female[(22] She suggests adding three more groups based on "intersex" humans: herms (true hermaphrodites who possess one testis and 1 ovary), merms (individuals who accept testes, no ovaries, but some female genitalia), and ferms (who take 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 unlike and mutually sectional factors may be at work in particular cases. It is an incommunicable and intellectually misguided job.

Two major studies examining the historical origins of modern sexual categories show how social groupings that evolve over time tin 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 non 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 every bit its date of birth[24]--less by a blazon of sexual relations than by a sure quality of sexual sensibility.... The sodomite had been a temporary aberration; the homosexual was now a species.

This assay, it seems to me, points to a critical error in the enquiry of both Hamer and LeVay. Both, in spite of their qualifications, prefer the idea of the homosexual as a physical "species" different from the heterosexual. Merely there are no convincing historical grounds for this view. Every bit Foucault points out, at the fourth dimension of Plato,

People did non have the notion of ii distinct appetites allotted to different individuals or at odds with each other in the aforementioned soul; rather, they saw two means 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.due east., that the discussion 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 than various. Basing his view more on intuition than on sociological evidence, he predicts "the declining significance of sexual orientation."

The last result that has dislocated the interpretation of research into sexuality is the significant 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 near his own position on biological determinism,

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

Both researchers ignore the central issue in the contend over nature and nurture. The question is: How do genes get y'all 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 archetype autumn-dorsum position is to claim that genes merely provide a basis, at near a predisposition, to a particular beliefs. Merely such statements lack a precise or testable significant.

Perchance we are request the wrong question when we set out to observe whether there is a cistron for sexual orientation. We know that genes are responsible for the development of our lungs, larynx, oral fissure, and the speech areas of our brain. And nosotros sympathize that this complexity cannot be collapsed into the notion of a gene for "talking." Similarly, what possible basis can there exist for concluding that in that location is a single gene for sexuality, even though nosotros 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, just merely to recast their function in a different conceptual setting, one devoid of dualist prejudice.

The search for a single dominant gene--the "O-GOD" (one factor, one disorder) hypothesis--that would influence a behavioral variant is likely to be fruitless. Many different genes, together with many different environmental factors, volition interact in unpredictable ways to guide behavioral preferences. Each component will contribute minor quanta of influence. 1 issue of such a quantum theory of beliefs is that it makes irrelevant the overstretched speculations of both Hamer and LeVay about why a factor for homosexuality still exists when it apparently has piffling apparent survival value in evolutionary terms. The quest for a teleological explanation to identify a reason for the being of a "gay cistron" becomes pointless when i understands that in that location is not now, and never was, a single and final reason for beingness gay or straight, or having whatsoever other identity forth the continuum of sexual preference.

Does this complexity, together with an adverse and polarized social milieu, preclude successful enquiry efforts concerning man sexuality? In 1974, Lewontin wrote that reconstruction of man's genetic past is "an activity of leisure rather than of necessity."[26] Perhaps then. Simply, every bit 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 order'south most pressing problems, such every bit drug corruption, 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 equally sense of well-being and the ability to dearest and piece of work.[27]

What research into human sexuality, and then, lies ahead? Dean Hamer has repeated his initial work among male person homosexuals in an entirely new group of families and has included a much-needed assay of women. He has also compared the frequency of the Xq28 marker amidst pairs of gay siblings and their heterosexual brothers, important control data that he did not acquire the first time around. This piece of 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 standing with his project.

To runway downwardly and sequence the DNA from one or more relevant genes at Xq28, from a total of about ii hundred candidates, seems an most insuperable task. To read the molecular script of DNA involves deciphering millions of elective elements. Moreover, each gene will take to exist studied individually and many more pairs of gay brothers will be needed to achieve this goal. The piece of work will exist extremely difficult for a single laboratory to undertake on its ain. Hamer'due south request for a federally funded centre 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 programme would be valuable.

The concerns of such an establish should be broad. For instance, it might have included the recent piece of work reported from Yale which overturns the conventional view that language function is identical for both men and women.[28] Past 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 merely the left side of their brains. If functional brain differences for sophisticated behaviors be between the sexes, the chore for the future would be to link part to construction and to describe how both evolve from a groundwork of genetic and environmental influence.

Inevitably, the idea of biological determinism carries with it the threat of manipulating the genes or the encephalon in order to adapt to the prevailing norm. Equally I have noted, Hamer was acutely enlightened of this possibility when he wrote his paper. Only the prospects for pinpointing genetic risk take moved apace and worryingly forward with the recent availability of genetic screening techniques for, amidst other diseases, several cancers, including a small proportion of cancers of the breast, colon, and thyroid. Nearly such techniques are used without any current prospect for gene therapy or for any other effective handling of the weather identified. Geneticists such as Francis Collins, director of the Human Genome Project, have opposed unrestricted and unregulated screening techniques, describing their recent uses equally "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 hateful little in the market place if his work eventually leads to the isolation of a gene that has an event on sexual preference, fifty-fifty if information technology has just a small effect that is present in just a limited number of people. Usa 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 Strength on Genetic Testing in April. The xx-fellow member commission includes representatives from industry, managed-intendance 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."[xxx] His committee is charged with performing a 2-twelvemonth study of genetic technologies, which will wait specifically at the accurateness, 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 United states 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 shut attention.

But sexual activity-based research has already see political trouble. The Council for Citizens Against Regime Waste has charged that some NIMH research is a misuse of taxpayer's coin. Tom Schatz, CCAGW'due south president, has criticized 20 such studies, including one involving research into sex offenders. Rex Cowdry, acting managing director of the National Constitute of Mental Health, argues that "for these grants, I call up commencement you have to believe that the factors that motivate and control sexual behavior are worth knowing about...you accept to believe that knowing more than about how men and women are both similar and different is important."[31]

With such partisan pressures dominating the future of the enquiry calendar, the apportionment 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, simply is socially constructed, therefore deconstructable.

LeVay and Hamer on the one hand, and Katz, on the other, plainly have taken completely antithetical positions. Only 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 every bit 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 nosotros assume that we already understand the differences between the sexes. In part the results of that inquiry ofttimes contradict any such assumption. Katz demands that "we demand 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.

Information technology is true that the research of Hamer and LeVay presents technical and conceptual difficulties and that their preliminary findings plain need replication or refutation. Nevertheless 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 discover an answer to the question, What does information technology hateful to be gay and/or straight?--offers the possibility of eliminating what can be the almost oppressive of cultural forces, the prejudiced social norm.

1 Run into 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 Run across Bernard J. Oliver, Jr., Sexual Deviation in American Order (College and University Printing, 1967), p. 146.

4 Meet Karen de Witt, "Quayle Contends Homosexuality Is a Affair of Option, Not Biological science," The New York Times, September xiv, 1992, p. A17.

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

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

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

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

9 Encounter 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.

x. The normal complement of human chromosomes is twoscore-six per private, 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 person carrier for homosexuality (XXh) produced offspring with a non-Xh male (XY). One-half of all female children would be carriers of Xh (like their mothers), while half of all male offspring would comport Xh unopposed by another X. The Xh trait -- homosexuality -- would then exist able to express itself.

11 Past gamble, ane would wait each pair of brothers to share one-half their Dna. Then, bold that at that place was no gene for homosexuality, 1 would look twenty of the 40 pairs of brothers to share the X chromosome mark.

12 LeVay has recently completed a 2nd book in collaboration with Elisabeth Nonas--Urban center of Friends--that surveys gay and lesbian culture; it will be published past MIT Press in Nov. He is currently working on Queer Science, a study of how scientific enquiry 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.

xiv For case, see David Weatherall, Scientific discipline and the Repose Art (Norton, 1995) who notes that "these findings should non surprise united states of america. Well-nigh every condition...reveals a complex mixture of nature and nurture," p. 287.

15 Come across R.C. Lewontin, Due south. Rose, and L. J. Kamin, Non in Our Genes (Pantheon, 1984).

16 Lewontin is not a total skeptic near 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-twoscore.

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

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

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

xx For instance, in a UK study (run across Anne M. Johnson, "Sexual lifestyles and HIV risks," Nature [December 3, 1992], pp. 410-412), although but ane.4 percent of men reported a male person 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'due south 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 Plenty," The Sciences (March/April, 1993), pp. 20-24.

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

24 Dr. K.F.O. Westphal became the starting time mod author to publish an account of what he described as a "contrary sexual feeling" (Die contrare Sexualempfindung), although the word homosexual was outset used in a private letter of the alphabet 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," Scientific discipline (April 13, 1990), pp. 183-188.

28. See Bennett A. Shaywitz et al., "Sex differences in the functional arrangement of the brain for linguistic communication," Nature (Feb xvi, 1995), pp. 607-609.

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

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

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

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