How science explains homosexuality

What determines sexual orientation

It is not known exactly. However, among the possible causes of homosexuality, scientists distinguish psychological and biological. Let's analyze them one by one.

Psychological reasons

For many years, psychologists have tried to find the cause of homosexuality. Freud thought it was all about a weak father or his absence. Other psychoanalysts blamed childhood erotic experiences, psychological trauma after incest, or fear of people of the opposite sex.

There were many theories, but no evidence.

Sometimes orientation is associated with upbringing, but this theory does not stand up to test. Children growing up in same-sex families become homosexual no more often than those raised in traditional ones. Moreover, the orientation is often different for brothers or sisters growing up in the same family.

Another fact in support of biological causes is homosexuality in animals. For example, 8-10% of domestic sheep wanted to spit on sheep. They are taken to mate only on other males. Maybe these rams experienced problems with their father in childhood, but this is unlikely.

In the book We Are Our Brain. From the womb to Alzheimer's Dick Swaab says homosexual behavior has been observed in 1,500 animal species, from insects to mammals. There are known cases of same-sex relationships in penguins, elephants, rats, albatrosses. Bonobos monkeys are generally completely bisexual - they use intercourse to make peace or unite to protect themselves from enemies.

It can be concluded that psychology has little to do with a person's sexual orientation and the real reason must be sought elsewhere.

Biological causes

Comparing people with different orientations, scientists have found some differences in the structure of their brains.

In gay men, one of the nuclei of the hypothalamus is smaller than in men with a traditional orientation. Moreover, in women and men, this nucleus differs both in the number of cells and in their volume. In gay men, the number of cells is the same as in all men, but the volume is less, about as in women. They also have different brain structures responsible for smell and circadian rhythms.

The brains of homosexual women are in some aspects more like a man's: they have a stronger connection between the cerebral hemispheres (lateralization) and less gray matter in some areas of the cortex and cerebellum.

Also, people with different orientations have different odor handling. In heterosexual men and women, information about pheromones of the opposite sex is processed in the hypothalamus, and all other odors are processed in the olfactory networks. In homosexual people, the reaction is similar, only the hypothalamus is activated in response to pheromones of the same sex.

The differences in brain structures suggest that sexual orientation has biological causes.

One might argue that the brain is plastic and changes in response to experience, especially in early childhood. And trauma, for example, can change brain structures and sexual orientation.

However, as we mentioned above, no psychological cause of homosexuality has been proven by research, and two centuries of attempts to "cure" homosexuality have come to nothing. Scientists are inclined to believe that the features are still congenital, and not acquired. And science has several theories about what could be causing this change.

Why people are born with a certain orientation

Scientists hypothesize that in both sexes, the same neural pathway determines sex drive. But in which direction he will turn and who will attract a person - a man or a woman - depends on many biological reasons associated with hormones and genetics.

Hormone levels during pregnancy

Scientists have noticed that women with congenital adrenal hyperplasia (ADH) are more likely to become lesbians. VHKN leads to increased sensitivity of the female fetus to testosterone - the male sex hormone.

The effect of androgens on the embryo can affect a girl's sexual orientation.

They also found that if the mother took the hormone diethylstilbestrol during pregnancy, the chance of having gay girls was greatly increased.

Immune response of the mother

There is an interesting pattern: each older brother increases the chances of the next being homosexual. Moreover, the number of older sisters does not matter.

This is thought to be related to the mother's immune response. Each subsequent pregnancy increases maternal immunity to male-specific fetal antigens. At the same time, the effect of maternal antibodies on the next male fetus increases.

Genetic changes

The X chromosome produces genes that affect sex, reproduction, and cognition. Therefore, the genes responsible for sexual orientation were looked for in it. And for good reason.

One experiment found a link between male sexuality and the Xq28 X chromosome genetic marker. It is the same for 64% of homosexual brothers.

Another reason was found in the features of the mother's X chromosomes. Since women have two such chromosomes, one of them is randomly inactivated, and genes are expressed from the other. But in some women, one X chromosome predominates in 90% of cells.

In mothers with heterosexual sons, this happens in 4% of cases, in women with one gay son - in 13%, and with two - in 23% of cases. This proves that sexual orientation is passed on through the maternal line.

Is it possible to change sexual orientation

Since doctors used to think that homosexuality was a consequence of childhood experiences, they tried to treat it. Tried to kill attraction with electric shock, drugs that cause nausea, shock and shame. The milder methods included hypnosis, thought redirection, and other forms of psychotherapy. There was little sense.

Of the 75 studies published between 1960 and 1985, only six actually showed whether the therapy worked or not. And it didn't work. The participants did not change their behavior outside the laboratory, they were not attracted to people of the opposite sex. Some of them lost their attraction to either sex altogether.

An analysis of eight more modern scientific papers (from 1986 to 2009) did not reveal a single qualitative study at all that could prove the effectiveness and safety of the technique.

The treatment doesn't work. Moreover, suppression of attraction and fear of punishment, on the contrary, can lead to inappropriate sexual behavior and cause health problems.

There is currently no evidence that sexual orientation can be changed in any way.

Scientific evidence confirms that people do not choose their sexual orientation. The only thing they can choose is to accept it or deny it, risking mental health problems.