To Study Unfettered

Researching the causes of sexual orientation should be guided by scientific, not social, concerns.

By | July 1, 2014

© HH5800/ISTOCKPHOTO.COMOur recent (not yet published) genetic linkage study of male sexual orientation predictably garnered considerable media buzz when I summarized the results during this year’s AAAS meeting in Chicago. Scientific findings concerning the causes of sexual orientation provoke intense public interest. One reason is that the topic is intrinsically interesting. Show me someone who denies interest in what makes some people gay and others straight, and I’ll show you someone who is remarkably incurious. Another reason is the widespread belief that such findings have important consequences for how homosexual people should be treated. In the U.S., pro- and anti-gay activists have long argued over the causes of sexual orientation. The belief that the causes of sexual orientation have important social consequences is wrong, however, and its persistence is bad for both science and human rights.

Pro-gay liberals tend to emphasize innate causes, and anti-gay conservatives “choice” and malleability. This well-established attitudinal correlation is based on faulty reasoning by both sides. Let’s start with the most common framing of the debate: whether sexual orientation is genetic or chosen. This framing is utterly mistaken. The complement of genetic is not chosen but environmental. If parents could influence children’s sexuality by giving them certain toys, this would be an environmental influence, but it would be absurd to say that children choose their sexuality. The unfortunate insertion of chosen/choice reveals a badly outdated understanding of the way the mind works, implying that one is free to choose one’s thoughts, feelings, and behaviors without consideration of prior causes, including genetics. No scientist I know believes this. There is a sense in which we have free will, to be sure, but that sense excludes sexual orientation. Sexual orientation is a pattern of desire, not of behavior—a man who wants to have sex with men but not women has a homosexual orientation, no matter what he does. A woman can choose what to do about her sexual feelings, but she cannot choose those feelings to begin with. So let’s ditch the words “choice” and “chosen” when we’re talking about sexual orientation’s causes.

A more sensible framing is whether sexual orientation is innate or socially acquired, or somewhere in between. Innate is a more general term than genetic, and sexual orientation appears to be far more innate than it is genetic. This is because the best twin studies of sexual orientation show unusually small concordance values for both monozygotic (MZ) and dizygotic (DZ) twins, compared with those for many other human traits. To be sure, twin studies support the likelihood that genes influence sexual orientation in both sexes, but that influence appears modest.

It is still worth searching for genes—if we can find them, we can learn a lot. We can also avoid the mistake of assuming that modest heritability of sexual orientation means that it is mostly due to social influences. It isn’t—at least, male sexual orientation isn’t. We know this because of a few important cases of boys changed into girls shortly after birth, due to medical accidents or rare birth defects. Later in life these males are attracted to females, consistent with their prenatal biology but not their postnatal rearing.

I love conducting research on sexual orientation, but I do not study it because it has any implications for how we should feel about homosexual people. Our attitudes about human characteristics should (and generally do) reflect consequences of those characteristics rather than their causes. If homosexual people caused great societal damage, the way that psychopathic people do, we would disvalue homosexuality, whether homosexuality were innate (like psychopathy appears largely to be) or learned. But they don’t, and we shouldn’t. I can’t imagine a plausible scientific result about the origins of sexual orientation that would justify prejudice against homosexual people. Conversely, data about the roots of sexual orientation should not enter, much less end, a debate that inherently belongs in the moral, not the scientific, realm.

Although liberals tend to like findings that sexual orientation is genetically influenced for the mistaken reasons I’ve noted, some fear that genetic research will lead to attempts to manipulate sexual orientation prenatally. I don’t think this will happen—the likely genetic effects are too small to be useful, even if one thought this was an acceptable goal.

But no one can see the future, and it is not inconceivable that research on sexual orientation will lead to knowledge about how to change it. I oppose any attempt to limit scientific inquiry due to the fear that this might happen. In the unlikely event that techniques are developed to influence unborn children’s sexual orientation, parents should have that right, assuming they aren’t harming anyone. Shaping children is an essential goal of parenthood, and in a democracy, we have to let parents pursue some goals even if we don’t share them. Changing a baby’s future sexual orientation isn’t harming the baby. (Worries about selective abortion are worries about abortion, a debate I don’t want to enter here.) The bioethicist Tim Murphy—who happens to be gay—agrees with me.

Sexual-orientation research is irrelevant to the rights of homosexual people, who deserve equal rights regardless of what those studies show. What, then, is the point of conducting them? Sexual orientation is a fundamental human difference, analogous to differences in personality, intelligence, attitudes, and interests, most of which have been studied with considerably less controversy. Understanding how and why people vary in these traits is important to understanding human nature. The belief that sexual-orientation science has clear social implications has led to politicization of this research, however. For example, I know several scientists who were asked by sympathetic administrators to change the titles of their research grants, to hide their intention to study sexual orientation from those who would oppose funding them for political reasons. This practice reflects outrageous politicization of legitimate scientific inquiry and should be unnecessary.

The mistaken belief that data supporting inborn causes of sexual orientation justify tolerance of homosexual people leads to the equally mistaken belief that tolerance of homosexual people requires such data. Recently, the government of Uganda claimed that there is insufficient evidence that homosexuality is innate, before criminalizing it severely. We are a long way from an adequate scientific theory of the causes and development of sexual orientation. There is no good reason why homosexual people should wait for us scientists before they can obtain their human rights. 

Michael Bailey is a professor of psychology who studies the genetic roots of sexual orientation at Northwestern University.

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Avatar of: James V. Kohl

James V. Kohl

Posts: 427

July 1, 2014

Re: "It is still worth searching for genes—if we can find them, we can learn a lot."

No experimental evidence from any model organism suggests that the biological basis of morphological and behavioral phenotypes that include sexual orientations is genetically determined. Since 1996, all experimental evidence of biologically based cause and effect has continued to attest to the fact that cell type differentiation is nutrient-dependent and pheromone-controlled. There is a model for that! From Fertilization to Adult Sexual Behavior

"Small intranuclear proteins also participate in generating alternative splicing techniques of pre-mRNA and, by this mechanism, contribute to sexual differentiation in at least two species, Drosophila melanogaster and Caenorhabditis elegans (Adler and Hajduk, 1994; de Bono, Zarkower, and Hodgkin, 1995; Ge, Zuo, and Manley, 1991; Green, 1991; Parkhurst and Meneely, 1994; Wilkins, 1995; Wolfner, 1988). That similar proteins perform functions in humans suggests the possibility that some human sex differences may arise from alternative splicings of otherwise identical genes." (p. 337)

Avatar of: Salticidologist


Posts: 40

July 8, 2014

There is a lot of non-scientific opinion in this article, but I agree with the premise that study of behavior should not be 'fettered by social concerns'. Science has no bearing on morality. For example, a biologist can determine that the male lion is furthering the propagation of his own genes by killing offspring of a different male. There are no moral ramifications of this, it just works that way. The notion that 'there is no free will' is highly presumptuous and it would be more accurate to say that 'objective science has presently no direct means to infer the existence of free will'. If one did find a genetic, or epi-genetic, basis for sexual attraction to a member of the same sex, there could be two different directions taken, neither of which has anything to do with science. One would be to treat a person with this character with gene therapy (or chemical therapy) to correct this anomaly. The other would be to celebrate the pleasure associated with accepting this anomaly as a norm. Science has nothing to do with the determination of which is better, because in science there is no good and no evil. The biologist, for example, considers maternal care of young to be selfish in the most profound sense of that term, and knows that all life exists at the expense of other life.

Avatar of: W. Boernke

W. Boernke

Posts: 18

July 8, 2014

"Pro-gay liberals tend to emphasize innate causes, and anti-gay conservatives “choice” and malleability."

I really wish pro-gay liberals would think critically about presenting an argument based on biological determinism.  The best argument against biological determinism is the Milgram studies that showed most people would act sadistically when ordered to do so by an authority figure.  In other words, people who readily would say it is immoral to hurt other people will still act immorally when ordered to do so.  (This is the Nuremberg defense: "I was just following orders.")

You can make an argument from evolutionary psychology that humans evolved this behavior (following orders).  Humans require long periods of learning.  A child who obeys an adult who tells her not to pick up that poisonous snake is far more likely to survive than a child who learns by trial and error.

Tennyson wrote in "The Charge of the Light Brigade": "Theirs not to reason why; theirs but to do and die."  In the military, it is absolutely crucial to follow an officers orders without question.

The problem is that just as the Nuremburg Tribunal convicted the Nazis for not disobeying immoral orders, our genes made us do it, is no escuse for behaving immorally.

A much better argument against homophobes is that homosexuality is simply not immoral.  The reason the Torah condemns sodomy is because sodomy breakes the commandment to be fruitful and multiply.  Because death rates were very high (famine, disease, constant war, etc.). birth rates also had to be high to maintain the population.  It was reasonable to condemn behaviors that prevented reproduction (e.g., sodomy and spilling your seed on the ground--Yahweh whacked old Onan for spilling his seed on the ground).

Does condemning sodomy have any relevance in the 21'st century?  Absolutely not, our population is 7 billion and being fruitful and multiplying will be the death of us all.  Homosexuals should be praised for choosing not to reproduce.

July 8, 2014

I have of necessity under oppression several times changed my sexual preference until I've become quite adept at it. While no one knows how I do this, this doesn't mean I haven't developed the behavioral technology (which may require a talent or certain IQ level) nor does it mean choice is not relevant to sexual preference. Sexual preference, in my experience, is a myth. What actually exists is bonding, getting into people's special spaces of the body and enjoying the security and mutual acceptance that that involves. We tend to repeat what we enjoy and know how to do, so we repeat doing that and it gets called a sexual preference. Actually, there's no preference, just bad grammar mislabelling things as sexual that are probably a matter of hygiene grooming activity such as the monkeys do while picking bugs out of each other's fur. Does that make monkeys pansexual, that they do it with all ages and sexes?  No. It makes them CLEAN!!!!

Avatar of: Dean Hamer

Dean Hamer

Posts: 2

July 22, 2014

Michael- I agree with many of your arguments.  However there is one clear, and important error,  Your statement that "The belief that the causes of sexual orientation have important social consequences is wrong" is simply incorrect.  


A variety of research approachs, both obervational and experiemntal, have shown that people?s beliefs about the causation of sexual orientation do influence their views on LGBT inclusion and equality.  What you meant, I?m sure, is that they *shouldn?t* make a difference.  

I actually agree, but then there are many things about human beliefs that I wish were otherwise, and this is one of them.



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