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 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.
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.
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.
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," he merely reasserted the belief that
homosexuality reflected psychological conditioning with little biological
basis, and certainly without being influenced by a person's biological
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" --of
homosexuality's origins being revealed in the lowly fruit fly, Drosophila.
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
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
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. 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. 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. 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 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...."
Fortunately, their somewhat hysterical reaction has been followed by more
careful comment by other scientists.
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
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 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. He
has described the separation of behavioral variation into genetic and
environmental contributions and the interaction between the two as
"illusory." 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,
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.
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
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. 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."
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." He denounced what he called "Freud's conformism"
in taking heterosexuality to be the normal standard in psychoanalysis. He
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--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. 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
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
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.
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." 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
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
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. 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
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" 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
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." 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."
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
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.
1 See Perversions: Psychodynamics and Therapy, edited by Sandor Lorand and
Michael Balint (Ortolan Press, 1965; first edition, Random House, 1956), p.
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.
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.
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
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,
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,
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.
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.