Erotic relationships between members of the same sex, ranging from sexual fantasies through kissing and mutual masturbation to oral or anal contact.Today it is a generally accepted fact that human beings cannot be divided into two separate and distinct sexual groups, one composed of a relatively small number of homosexuals and the other a relatively large number of heterosexuals. Rather, there is a continuous line between these two poles, with many individuals sharing both tendencies to a greater or lesser degree. Some investigators believe that all of us are in some degree bisexual, although the homosexual component remains latent in the majority.At any rate, there is evidence for a widespread potential for homosexual response in Kinsey’s estimates (1948, 1953) that 50 per cent of males and 28 per cent of females have engaged in overt homosexual activity at least occasionally. The number of persistent cases—men or women who can be termed active homosexuals—is much smaller. It has been variously estimated at from 2 to 8 per cent of the population.In recent years there have been two competing approaches to homosexuality, the constitutional and the psychosocial. The constitutional approach emphasizes heredity, chromosomal differences, and hormone balance. Kallmann’s twin studies (1953) seemed to give impetus to the hereditary explanation, since he found a concordance rate (both homosexual) of 100 per cent in identical twins, and only 40 per cent among fraternal twins. Yet identical twins usually spend more time together than fraternal twins, and are often subjected to the same experiences—in other words, they probably do not develop their homosexual patterns independently. Similar interpretations may apply in the few cases where homosexuality seems to run through two or more generations. Moreover, some individuals shift from exclusively heterosexual to exclusively homosexual patterns, or vice versa, in the course of their lives, and this shift could hardly be the result of heredity. Genetic factors, therefore, appear to be highly debatable.The recently suggested hypothesis of chromosomal differences seems to be even more questionable. Although anomalies do occur—for example, a male with two X chromosomes, which is normal for females—they do not necessarily affect sexual behavior. Some early studies seemed to indicate that homosexuality is the result of an abnormal androgen-estrogen ratio, but recent investigations have failed to support these findings. Moreover, hormonal imbalance occurs in many nonhomosexuals, and it is known that people may shift their sexual pattern without a shift in hormone balance. Also, medical treatment with sex hormones does not change the direction of sexual interest. At most all these constitutional factors play an interacting rather than a determining role in homosexuality.The emphasis today is increasingly on psychological and social explanations. The sexual impulse is somewhat amorphous during the child’s early years, and it is quite possible to encourage it to take a homosexual direction even in a predominantly heterosexual society. One of the major influences is early homosexual experiences. Bieber and others (1962) have shown that well over twice as many homosexual as heterosexual individuals have had such experiences in childhood. These incidents were usually repeated many times and were reinforced by physical pleasure. In many cases the young person also derived comfort and emotional support from the person with whom he had the experience. This is believed to be an important factor in establishing the homosexual pattern.A second major influence is distorted family relationships. An unhappily married mother may establish a pathologically close relationship with her son, and even act seductively toward “mummy’s little lover.” A boy also becomes extremely attached to his mother if the father is absent from home, extremely harsh to him, or domineering and yet basically weak (Bender and Paster, 1941). Some authorities believe that attachment to the mother encourages the boy to identify with the feminine role. Others believe that the mother discourages the boy’s masculinity in order to suppress his incestuous impulses as well as her own, since these impulses arouse guilt feelings. Moreover, the boy who feels guilty about his feelings toward his mother may later on avoid all relationships to women because they remind him of the forbidden mother.Boys who become pathologically attached to their mothers usually fail to learn how to be a man through the normal process of identifying with their father. Frequently the father actually refuses to serve as a model because he rejects the boy as a rival. This, however, is not the only distorted family pattern. In cases where the father shows a marked preference for a daughter, the son may wish he were a girl. Such a wish may remain latent for a long period and later manifest itself as overt homosexuality. In other cases the mother may be so hostile or detached that the boy acquires a dislike or fear of women, and later turns to his own sex for satisfaction.The end result of these distorted family relationships is that the boys become dependent on their mothers, closely identified with them, and develop traits of timidity and effeminacy that make them shy away from masculine activity of any kind. Bieber found that less than one- fifth of the male homosexuals he studied had participated in typically masculine games. Practically all of them had been humiliated and rejected by other boys. He therefore concluded that “failure in the peer group, and anxieties about a masculine, heterosexual presentation of self, paved the way for the prehomo- sexual’s initiation into the less threatening atmosphere of homosexual society, its values and way of life.”Several other influences have also been stressed. Occasionally a boy becomes identified with femininity because he has actually been raised as a girl in early childhood. Similarly, a girl may want to play a masculine sex role because she has been reared as a boy, or may think that it is better to be a boy than a girl. The attitude of one or both parents may determine that preference. The psychoanalytic theory focuses on “castration anxiety”: homosexuals are motivated by unconscious fears associated with losing or being deprived of the penis. The male homosexual therefore avoids women because they remind him that he may be castrated; he can only function with a “woman with a penis.” The female homosexual, on the other hand, avoids males because they remind her that she has already been castrated; she can only function with women because they do not arouse “penis envy.”Finally, homosexuality may arise from social contact. Both males and females become involved in homosexual behavior in correctional institutions, military service, or boarding schools, where they are in close contact with members of their own sex and at the same time have little or no opportunity for heterosexual relationships. This is sometimes called accidental or pseudohomosexuality, to distinguish it from the type that results from faulty development. These individuals do not consider themselves homosexuals and usually change back to heterosexual behavior when they have an opportunity. Some, however, remain homosexuals, and a few—particularly men who have served a long prison term—have been found to seek out children or adolescents of their own sex after they have been released.Therapy for homosexuality presents a difficult problem. Most homosexuals believe their tendencies are inborn or the unalterable result of familial influences operating early in life. Many have accepted and fully rationalized their way of life, particularly if they belong to a fairly well organized “homosexual community.” They are more likely to seek help because social disapproval and fear of detection have made them anxious or depressed than because they want to change their sexual orientation.Some homosexuals, however, seek to alter their pattern through psychoanalysis or other forms of psychotherapy, and25 to 30 per cent of these patients succeed in becoming heterosexual. One promising new approach is the conditioning program designed by Freud (1960). The male patient is given an emetic which makes him vomit, and while he is sick he is shown slides of dressed and nude males. Later on he is given an injection of the male hormone, testosterone, to increase his sex drive, and he is then shown films of nude and semi-nude women. Follow-up studies indicate that the treatment is fully effective in at least 25 per cent of cases.Not all therapists attempt to alter homosexual patterns. Some believe that it is more practical to help the confirmed homosexual to accept himself as he is, provided his relationships are confined to adults. Others insist that all homosexuals are emotionally disturbed and in need of treatment because they are inevitably haunted by a sense of guilt, although this feeling may be more deeply buried in some than in others. See TRANSVESTISM, TRANSSEXUALISM, CASTRATION COMPLEX, PENIS ENVY, BEHAVIOR THERAPY, HOMOSEXUALITY (FEMALE), HOMOSEXUALITY (MALE), SEX ROLE.