Genuine interest in science is manifested in relation to those features of human behavior that, from the point of view of public morality or religious ethics, are considered unacceptable, harmful and dangerous. Homosexuality is just one of these features, the study of which is very intensively engaged by scientists in many countries of the world.
Genetic studies of homosexual orientation – often referred to as studies of “homosexuality genes” – have always caused fierce debate not only in academia, but in society as a whole. These studies have been going on for more than a hundred years, but especially recent finds have attracted close attention.
Hairy face – means gay?A scientific study of sexual orientation has gone through several stages. The first direction included the search for evidence of a person’s sexual orientation in such morphological characteristics of the body as the amount of facial hair, the size of the external genital organs and the ratio of shoulder width to hip width. Today, morphological studies have become more sophisticated, switched to the study of neuroanatomical structures.
In such a study, it is usually assumed that sexual orientation has two characteristic forms: one is associated with the male sex, the other with the female. Researchers who proceed from this assumption expect that individual features in the structure of the brain or physiology of the individual will correspond to the male type, which leads to a sexual desire for a woman (characteristic of heterosexual men and lesbians) or the female type (characteristic of heterosexual women and gays). However, this assumption has not received scientific justification.
Or maybe it’s hormones?
Another early approach sought evidence of a person’s sexual orientation in his endocrine system. The idea was that gay men androgens (male sex hormones) have less or more estrogen (female genital organs) than heterosexual men, and lesbians, respectively, vice versa. However, the vast majority of works within the framework of this theory were not able to demonstrate at least some connection between the mature hormonal system and sexual orientation.
According to existing hormonal theories of sexual orientation, gays and lesbians at an early stage of development were affected by the level of hormones atypical for them. Such theories stubbornly cite observations that changes in the hormonal level in rodents in the early stages of development lead to changes in the brain, causing changes in the ratio between male and female stereotypes of mating games at a later age. The transfer of the behavior of rodents to the phenomena of the human psyche, however, is very problematic.
The genes were to blame, but still
Since human behavior depends not only on its genetic structures, but also on external, social conditions, studies have begun to include in the range of issues studied the influence and interaction of these factors on the process of formation of sexual orientation.
The well-known work of Bailey and Pillar was based on the observation of twin brothers.
In particular, studies have shown that in identical twin couples the sexual orientation of the brothers coincides (both twins are either heterosexual or homosexual) in 52% of the total number examined, while in non-identical brothers this figure was 22%.
Considering the fact that identical twins have the same conditions of family upbringing and a genetic set, a half mismatch in their sexual orientation indicates that environmental conditions make a significant contribution to its formation. However, a significantly higher number of coincidences of sexual orientation in identical couples compared with heterogeneous couples indicates that the same genetic set also influenced its formation.