Sexual Orientation

Dr. C. George Boeree

In Tajik: психологияи умумӣ (translated by Sherali Jalolov)

The roots of homosexuality are still a mystery - although only a little more a mystery than the origins of heterosexuality!  Like almost everything, it is likely to involve both genetic-physiological roots and cultural-learning roots.  Here are some of the possible factors:

First, there may be genetic foundations for homosexuality.  J. Michael Bailey and Richard C. Pillard, for example, discovered that 52% of the identical twins of male homosexuals were also homosexual, compared to only 22% of non-identical twins.  Likewise, they found that if one identical twin is lesbian, in almost 50% of the cases studied, the other twin is lesbian as well, in comparison to 16% of the non-identical twins.

People always ask:  If homosexuality is genetic, how does it get passed on to future generations?  Homosexuals do have children, of course, but at a considerably lower rate than do heterosexuals.  So why hasn't it "evolved out" of us?  There are a number of possibilities, but the most obvious one is that the genes responsible for sexual orientation are similar to those simpler genes that account for sickle-cell anemia:  If you have a sickle-cell gene from mom and a sickle-cell gene from dad, then you will get sickle-cell anemia, a deadly disease.  But the sickle-cell gene remains a part of the population because, if you only have one of them you will be more resistant to malaria!

In the same way, if you inherit a "full dose" of genes for homosexuality, you may be less likely to reproduce.  But a "half dose" may actually make you more likely to survive and reproduce.  Women with some characteristics more associated with men (men's assertiveness, perhaps?) may do better than their more feminine sisters.  Likewise, men with some characteristics of women (perhaps more affection for their children?) may do better than their macho brothers.

Even with a genetic component to homosexuality, we need to understand that genes are only responsible for the making of proteins, and we still need to explain how a protein can influence our sexual behaviors.  One fruitful path is, naturally, the "sex hormones," especially testosterone and estrogen.

Estrogen, the female hormone, is the default hormone:  If testosterone is not present in a developing fetus, it will develop into a girl, whether it actually has the genetics of a female or not.  On the other hand, if testosterone is somehow added to the developing fetus, it will develop testes, a penis, and so on, even if it has the DNA of a female!  There are certain circumstances where these events occur.

Both men and women have testosterone - it is crucial to growth - but men have something on the order of 100 times the amount.  In rats and mice, low levels tend to be associated with lordosis, which is the technical term for the sexual posture that female animals tend to take.  High levels in animals is associated with a tendency to mount other animals.

Men with higher levels of testosterone tend to have a more masculine appearance, tend to behave in a more masculine fashion, and tend to be more aggressive.  Men with less testosterone tend to look and act somewhat more like women, and women with more testosterone than other women tend to look and act somewhat more like men.  However, there is no overpowering connection between testosterone levels and homosexuality in human beings:  Researchers have found no differences between male homosexuals and heterosexuals when it comes to how much testosterone is circulating in their blood.  Apparently, our sexual orientation is a bit more complicated than that of rats and mice!

Some other studies suggest that there are differences in the way that men and women respond to estrogen:  Women respond by producing more of a pituitary hormone called luteinizing hormone or LH.  Men do not.  But homosexual men responded more like women, which suggests that homosexual men have a more "female" hypothalamus.  We would then expect that lesbians would have a more "male" response, but that is not the case.  In fact, they respond with even more production of LH than heterosexual women do - as if they were more "feminine" rather than less!  This suggests that homosexuality works differently in men and women.

There have been studies of brain structures, looking for differences between men and women and between heterosexuals and homosexuals.  Some small differences have been tentatively identified, but the research is still only in its early stages.  And we have no way yet of knowing if these differences cause the hormonal differences, or are caused by them!

Still, the argument that at least a good portion of our sexual orientation is biological is hard to deny.  Homosexuals often say that they have felt an attraction to the same sex as long as they can remember.  And studies by Martha McClintock and Gilbert Herdt show that both homosexuals and heterosexuals develop attractions to the same or opposite sex at around the age of ten, two or three years before they begin developing the clearer signs of puberty.  With heterosexuality our clear cultural norm, we should not see any same-sex attraction if it were only a learned behavior!  Instead, we see somewhere between 3 and 10% of the population considering themselves homosexual.  (The figures are so ambivalent, no doubt because of that cultural norm!)

The relationship between an instinct and upbringing is a matter of imprinting:  The precise nature of a complex stimulus is usually not directly supplied in the genetic programming of the brain.  It is more efficient to program the brain to attach an instinctual response to a stimulus while experiencing that stimulus. So goslings follow the first large moving object they see, to use the classic example.  There is also a critical period involved during which this imprinting occurs.  For geese, this is a matter of a couple of days.

Freud’s theorizing about sexual orientation is basically the same as this.  During a critical period - which he felt was between the ages of three and six - sexual orientation is fixed by a complex process of family relations he called the Oedipal crisis.  A young boy begins by being attached to his mother.  As he gets older, he acknowledges his father’s priority in relation to mom, and substitutes girls and later women for mom as his primary sexual interest, and begins to identify with his father, from whom he learns what it means to be male.  A similar process, with complications, occurs in young girls.  Freud’s explanation is muddied by his use of the bizarre concepts of castration anxiety (the supposed fear boys have of losing their penis) and penis envy (the supposed desire girls have for growing one).

Like most psychologists, I don’t agree with too much of Freud’s theory.  But there is some sense in it:  I suggest that, by the age of 3 or 4, social learning has already informed the child of their gender, and has (for most) strongly reinforced identifying with the same sex parent.  The relation between mom and dad becomes the model for the child, and later sexual fantasy centers around the gender of the opposite sex parent.  This may be reinforced by the opposite sex parent playing the part of "role reactor," that is, by engaging in non-sexual flirtation with the child ("daddy’s girl" and "momma’s little man," and the like).

Freud once said that infants are "polymorphously perverse," by which he meant that they enjoy sensual pleasure in any form, from any source.  I agree with him on this.  It takes the imprinting process to focus our sensual, and later sexual, enjoyments on one gender or the other.  If that imprinting process is disturbed in some fashion from the culturally traditional one we just talked about, we may find the child tending towards sexual orientations other than the purely heterosexual

This could happen in many ways: A parent or parents may encourage a child to identify with the opposite sex by treating them as if they were in fact that gender, or by overvaluing that gender insome way; the parent may not demonstrate the usual heterosexual stereotypes, or may be a more powerful role model which the child comes to identify with; in a one-parent household, the child may not even have a role model, or a role-reactor with whom to practice their gender identity; or a boy in a large family of girls or a girl in a large family of boys may be overwhelmed by role models of the opposite sex. But any of these is not likely to have much effect if there isn't already some more innate leaning in one direction or another.

(Note that, while I use words like parents and mom and dad, the same roles in the family dynamic may be taken up by other relatives and close non-relatives.)

If we take both the genetic-hormonal explanation and the family-learning explanation into account, we may have the beginnings of an understanding of homosexuality (and heterosexuality):  A boy or girl who leans towards homosexuality biologically, and who has a family situation that encourages that leaning, is more likely to grow up gay or lesbian or bisexual.  One who has neither the biological tendency nor the family situation is more likely to grow up straight.


Negative attitudes towards homosexuality are common, but the arguments for the negativity are very weak. For example, some people say that homosexuality is not natural. But it is found in many cultures and periods of history. One famous example is ancient Greece: Relations between men and between men and boys, were seen as normal and even superior to relations between men and women. In that tradition, a successful man would take it upon himself to take a promising young boy "under his wing", so to speak, as the boy's mentor - which included sexual relations. This has been true in many other cultures. The ancient Egyptians, Chinese, and even the cultures of western Europe since the fall of Rome included mentoring relationships of this sort, although typically secretive due to the overall negative attitudes.

The idea that homosexuality is not natural is often supported by pointing to its absence among animals, and the argument that, because homosexual activities do not lead to reproduction, the laws of natural selection work against it spreading within a species. The problem is that neither of these things are accurate. First of all, many hundreds of species do in fact include homosexuality. Secondly, homosexuality need not restrict an animal from heterosexual relations, and may even include qualities that enhance survival and reproduction, such as the presence of more nurturant "maternal" instincts in some individuals with a proclivity to homosexuality.

Some might argue that, even if it is found in nature and other societies, certainly it is "abnormal" and so unhealthy mentally or physically. But they fail to remember that left-handedness is also abnormal, as it red or blonde hair, blue or green eyes, perfect health, extreme physical strength or agility, high intelligence, etc.

One of the reasons that homosexuality is, in fact, statistically less common, is that marriage has, until fairly recently in our society and most others, much more than sex. It is more of a social, economic, and even political relationship, involving alliances between families and even nations, a matter of determining inheritance and improving status and wealth of one or another family, and so on. Marriage has often been something arranged by parents or others in authority. More recently, marriage is based on individual and personal attraction and compatibility, that is to say, on love, and there is no evidence that love is restricted to heterosexuals.

Most societies place a great deal of importance on marriage, and therefore keep a degree of control over it. As many old hippies have noted, why should one's relationship be certified by authorities and a legal document? But the well-being of those in power often depends on how well they control the activities, including sexuality, of their subjects or citizens. The same can be said of religion. Large and powerful organized religions have often spent far more effort on controlling their "flock" than in promoting compassion and helping each other.

In western societies, the "Abrahamic" religions - Judaism, Christianity, and Islam - have predominated. All three have, until recently, been strongly patriarchal and controlling towards women, and by extension, disparaging of female behaviors among men. Many societies have survived and thrived by emphasizing strength and aggressiveness over nurturance and peacefulness, i.e. "male" qualities over "female" ones.

People in the west who object to homosexuality with often point to the Bible (or other scripture) for support in their beliefs. However, the Bible actually has very little to say about the matter:

In Leviticus, it says that a man lying with a man is an "abomination". But this is a misreading: the word actually means "taboo", which is also true of having sex with your wife during her period, eating pork, crabs, and lobsters, working on the sabbath, and many more. In the story of Sodom (the source of the word sodomy - anal sex), the Bible says that God destroyed the city because they ignored the rules regarding hospitality, which were very important to the ancient Jews. Ezekiel says that God destroyed them because of their "arrogance, abundant food, and careless ease" and "they did not help the poor and needy" (16:49).

One needs to note that, in the Bible,"to know" someone almost always means the same as it does today, and not having sex with someone. Of course, if we were bonobo chimps, our closest primate relative, we would be very likely greet each other, whatever our gender or relationship, with some sex.

Although Paul does have something to say about homosexuality, especially in the case of ritual prostitution of priests in pagan temples, Jesus never says a single word about it.

There are some countries in which the taboo against homosexuality still remains: It is illegal in most Moslem countries, some African countries, and in India. In Saudi Arabia and Iran, imprisonment and even the death penalty may apply. But most countries in Europe, the Americas, Australia, and New Zealand have legalized it and permit marriages between two people of the same gender. Russia and China have also decriminalized it, with some restrictions.

If a culture is strongly anti-gay, if the dominant religion ingrains its prejudices in its children, if the community demonstrates its distaste repeatedly and consistently, homosexuality will tend to be driven underground. If homosexuality is viewed as just another way to be human, and prejudice is strongly discouraged by the society and religion, if there are enough role models to help people who incline to homosexual relationships, those people will be able to live happy and productive lives, without any harm done to those who prefer a heterosexual lifestyle.

There is one thing I can say about homosexuality with great confidence: Being homosexual, or deviating from the cultural norms in any way, in no way makes you less of a human being, less worthy of respect, less deserving of dignity. Neither is one exempt from our propensities for misbehavior. But homosexuals have contributed enormously to humanity. An enormous number of famous artists, writers, scientists, and world leaders - as well as "ordinary" people" - have been something other than "straight"! Those who looked down on gays and lesbians are only revealing their own ignorance.


© Copyright 2002, 2009, 2019, C. George Boeree