Genes And Sexual Orientation, Behavior: Is There A Connection? - Research

What do we know about the contribution of genes to sexual orientation? This is one of those topics that people simply cannot resist, says neuroendocrinologist, professor of biology, researcher Robert Sapolsky

Robert Morris Sapolsky is an American neuroendocrinologist, professor of biology, neurology, and neurosurgery at Stanford University, researcher and author of books. In addition, he is a Research Fellow at the National Museum of Kenya. Sapolsky is a professor at Stanford University in a number of departments, including the departments of Biological Sciences, Neurology, Neurological Sciences, and Neurosurgery.

What determines a person's sexual orientation?

Scientific works confirm the presence of a certain degree of heritability of sexual orientation. Studies in twins have shown that about half of them have the same sexual orientation. Translated into normal language, if you are gay, then your twin brother has a 50% chance of repeating this story. However, among not twins, but simply blood brothers, such sexual repetitions are only 9%.

Thus, the more genes you share with someone, the more likely you are to share their sexual orientation

One can, of course, criticize the limitations of this interpretation. The role of genetics must be supported by other factors as well. Consider, for example, the story that became a sensation in the nineties. Genetic scientist Dean Hamer discovered the first genetic markers of sexual orientation, and this discovery made him famous. True, since then it has become the greatest difficulty to reproduce the results of his research. This has never been done.

It has become a tradition in the context of a conversation about genes to talk about evolution, proteins created by these genes and intrauterine development, causing genetic changes, gene transcription

Recall that evolutionary biology emphasizes the essence of sexual behavior on reproduction. Scientists who have studied rodents have confirmed that, indeed, sexual activity is manifested only during ovulation, aimed at reproduction, the transfer of a copy of genes. But this theory soon began to fall apart: it turned out that we (humans) were far from unique in non-reproductive sex. Bonobo monkeys became the leading species in this area.

The most sexually licentious species on Earth

From the point of view of specialists, bonobos are the coolest primates in the world. And unlike other chimpanzees, they have no sexual dimorphism.

Sexual dimorph - anatomical differences between males and females of the same biological species. Sexual dimorphism is more pronounced, the more different are the contributions of both sexes to offspring care. It is also an indicator of the level of polygamy

In the bonobos, females dominate sex, not males. Moreover, their couples can be safely described as sex giants with a record amount of sex. It would seem that such a species with low aggression and without sexual dimorphism should represent a typical monogamous species, but this does not apply to bonobos. On the contrary, before us is the most sexually licentious species on Earth.

Bonobos are dominated by promiscuity. They do not fit into our typology of doubles and tournament types. And there are many such sexual exceptions all over the planet.

It turned out that non-reproductive sex occupies a much larger niche in different species than many previously thought. And this greatly weakens the classical Darwinian view of the importance of sexual selection

Group-bond sex

A common theory is that unrestricted sex, like other activities, is needed for social purposes - for group cohesion. If you look at other species of primates carefully, you can see that when they are upset about something, they comb each other, and when they are happy - they also comb out. This is social grooming.

Bonobos' sexual behavior serves the same purpose: group cohesion, stress relief, conflict resolution. And this runs counter to the theory of the beginning of the last century, which we owe to the British Sulli Zuckerman

From his point of view, sexual behavior is influenced by the fact that females are more choosy in choosing a pair. This is due to the cost of pregnancy, childbirth and the difficult process of raising offspring. However, there is an exception to the rule: in couples such as marmosets, males have as much parental care as females.

Characteristically, many males attempt to control female reproductive behavior. This can be observed in many species in a banal version, when males fight with each other for the female. This is definitely true for humans as well.

Baboons, for example, implement a linear breeding access model. Its essence is as follows. If at the moment one female is ovulating in a group of baboons, then the main male mates with her. If there are two, then they go to numbers 1 and 2 in the hierarchy, and so on. The choice of females is of no interest to anyone.

Do females choose partners?

For a long time, it was believed that females did not choose partners. However, it has recently been found that this pattern is being violated. And they noticed this at the moment when mainly women began to work as primatologists. Then the shocking concept of some degree of freedom of choice for females was born.

It turns out that females are able to choose with whom to mate. But they cannot "beat" the male and go to another. They begin to cheat and harass the first sex applicant. When he sits down to eat, the female gets up and leaves, and he has to follow her. When he goes to bed, she again demonstratively leaves, and he has to walk with her. For baboons, the main trick is to go for a walk right in front of the main rival of the male. The female will do this over and over again until the two males fight and she runs away into the bushes, where she mates with the guy who really interests her.

What do females really want?

Scientists are still not completely sure, but there is one trend: females mate with those males who are kind to them. Thus, if you are a low-ranked male, then you do not burn out, do not get injured and you do not have to fight with other males. And at the same time, you live longer and reproduce longer.

Why do females like "good guys" so much? Attachment to them is built on the fact that they get along well with their cubs.

The development of these scientific theories may lead to the fact that the classical view of the mechanism of sexual selection, the relationship of genes and sexual orientation will be revised

More about this:

1. Sapolski R. Biology of Human Behavior: Lecture No. 16. Sexual Behavior, II. URL:
2. Sapolski R. Who are we? Genes, our body, society. M.: Alpina non-fiction, 2018.
3. Sapolsky R. Biology of good and evil: how science explains our actions. M.: Alpina non-fiction, 2018.

Expert opinion

Elena Malakhova, psychiatrist, psychotherapist, sexologist, full member of the All-Russian Professional Psychotherapeutic League, member of the professional association of sexologists

There is an observation of a group of gorillas. The alpha male is under constant stress to ensure the safety and survival of his group. Stress leads to a weakening / loss of his fertility. The female, when mating with the alpha male, does not produce offspring. Thus, assistance in raising offspring and procreation is provided by less ranked males in the group.

Let's draw a conditional analogy with the human "alpha male". Such men look incredibly seductive in the eyes of women. At the same time, they are not very suitable for family life. Their main goal is to prove to everyone and to themselves that I am the best. This behavior is based on childhood narcissistic trauma. Even in caring for their family, they do not consider the needs of others. For them, a wife and children are an extension of themselves. A woman in a relationship with an alpha male is forced to put up with his nature and endure discomfort. Or choose a less ranked and more comfortable man for life.