Homosexuality refers to relations between men or between women who experience an exclusive or predominant sexual attraction toward persons of the same sex. It has taken a great variety of forms through the centuries and in different cultures. Its psychological genesis remains largely unexplained. Homosexuality may lead to exploitation by blackmail, robbery, or sexual violence. In some countries, homosexuality is a criminal offence.
Male homosexuality, condemned in Judaeo-Christian society as the 'sin of Sodom', was condoned and even exalted in ancient Greece. Female homosexuality, or Lesbianism (recalling the poetess Sappho, who lived on the island of Lesbos and wrote love poems to women), is consistently condemned. Particularly since the liberalization of the law in England and Wales, and the foundation in America of the Gay Liberation Front, male and female homosexuals in these and many other Western countries have become less secretive about their way of life. Until the early part of the 20th century, homosexuality generally meant a form of sexual perversion. With the development of psycho-analysis, less emphasis was laid on sex-proper and a correspondingly broader connotation assigned to the term sexual. In current usage, overt homosexuality refers to physical, sexual contact between members of the same sex, while latent homosexuality is used to refer to impulses and desires toward a member of the same sex which are unconscious or, if conscious, are not openly expressed.
While sexual relations between two men or two women may be accepted in certain societies, and regarded as normal or at least tolerated (such as male homosexuality in Asian cultures), male homosexuality is particularly despised in Anglo-American culture and female homosexuality, although less reviled, is generally unaccepted. Recently homosexuality has come to be slightly more tolerated in 'Western' culture with the influence of the 'permissive society'.
Presently, there exists no scientific consensus on the causes of homosexuality or, for that matter, of heterosexuality. However, because traditionally homosexuality has been viewed in most Western societies as a divergence from normal sexual development and orientation, a wide variety of theories regarding its causation have arisen. Such explanations currently can be grouped as biological, psychoanalytic, and social learning theories, or some combination thereof.
An example of a biological theory is from a study done in the Netherlands. Thirteen of 15 brains of homosexual men who died of AIDS had suprachiasmatic nucleus (SCN), a part of the hypothalamus, was twice the size of a comparable group of heterosexual men and women. Two of the 15 who not thought to be homosexual had normal SCNs. This small group of cells helps regulate the rhythms of waking and sleeping, hormone secretion and sexuality.
Since male homosexuality appear to run in families, another biological explanation lies in genetics. In 1973, a research team reported that the appeared to be a linkage between DNA markers on the X chromosome and male sexual orientation. In 1995 researchers at the US National Cancer Institute reported evidence that genetic material on one segment of the X chromosome seemed to influence the probability of homosexuality in men, though not in women.
The traditional psychoanalytical view is that homosexuality is an acquired psychological condition reflecting a divergence from normal development. Most theories of this type emphasize the importance of early relationships with parental figures. Usually this figure is considered to be the mother in the case of male homosexuality.
Social learning theories suggest that, in some cases, an adolescent may be repelled by certain physiological aspects of the female personality. In others he may be afraid of not being able to play the role society expects of him in his relations with the woman his education assigns him as a partner. These apprehensions may lead to homosexuality if there are no moral prohibitions on this practice.
A theory favoured by militant homosexuals, is that homosexuality does not need any explanation, since it is an inherent potentiality in all of us and is repressed in most of us only by education and social pressure.