The term homosexual is applied both to persons who have a strong preference for sex partners of the same sex and to those who regardless of sex preference engage in sex relations with persons of the same sex.According to Ford a capacity to respond sexually to both sexes is present among humans and many other species.Homosexuality appears at least occasionally in all or nearly all human societies. It is either absent, rare or secret in about one third of the societies studied by Ford and Beach. In about two-thirds some form of homosexual behavior is considered acceptable and normal for at least some categories of people or stages of life. Homosexuals are very much like heterosexuals in every thing except sexual preference. A number of studies have found no other personality traits that distinguish homosexuals from heterosexuals. Apart from difficulties arising from the social treatment of homosexuals, personality maladjustments are no more common among homosexuals than among heterosexuals. The mental illness theory sees homosexuals as victims of sex-role confusion. According to psychiatric opinion the male homosexual is often a product of a dominating but seductive mother and a cold remote father. But the most comprehensive research study of homosexuals comparing large samples of homosexuals and heterosexuals found no significant differences in family backgrounds, parental types or relationships with parents. Several studies have found significant differences between the hormone levels of homosexuals and heterosexuals.
The social –learning theory holds that one learns homosexual behavior through the same reward-punishment system that shapes most social learning. According to this theory if most childhood and adolescent interaction with the opposite sex is pleasant and rewarding one becomes a heterosexual; if these experiences are uncomfortable and anxiety laden and if attempts at heterosexual intercourse are unsatisfying one may become a homosexual. The increased social acceptance of homosexuals in recent years has apparently not increased the number of homosexuals as expected if homosexuality were a learned sex role. There is no convincing evidence that having a homosexual parent, uncle or neighbor increases the likelihood of a child's becoming a homosexual. It is difficult to agree upon rational set of social policies concerning homosexuality unless more research and studies are carried out.