In a national random survey on the prevalence of same-sex sexual behavior in the United States, 10% of adult men and 9% of adult women report at least one of the following: (a) currently attracted “mostly” or “only” to same-sex persons; (b) same-sex sex “somewhat” or “very” appealing; or (c) had engaged in sexual behavior with same-sex person since age 18. Comparably, the prevalence of left-handedness in the population is 8%.
3% of men and 1.4% of women self-identified as gay, lesbian, or bisexual. This level of prevalence is similar to those who are Jewish in the United States, which is 2%-3%. Cross-cultural studies have shown prevalence of homosexuality to be about 5-6% for males and 2-3% for females when it is defined as an almost exclusive preference for members of the same sex.
Same-sex behaviors can be witnessed among most species of animals. There are several species whose rates of homosexuality exceed that of humans. For example, approximately 9% of rams show almost exclusive same- sex preferences and another 23% exhibit bisexual preferences. (more about same-sex behaviors in animal species and the implications for humans comng soon)
Scientists initially proposed theories of sexual orientation in the late 1800’s. Explanations before this time were mostly religious in nature. There are currently two broad categories of scientific theories of sexual orientation: environmental and biological.
Several studies have shown that people who believe homosexuals are “born that way” tended to be more tolerant and accepting of gays and lesbians, while those who believe homosexuality is due to learning or “free will” tended to be more hostile toward homosexuals. But the causal effect is likely to be the reverse – that attitudes toward homosexuality often influence beliefs about causality, in that individuals are likely to find most plausible those beliefs that best rationalize their attitudes.
Homosexuality was removed from classification as a mental disorder in America in 1973. However, the categories of gender identity disorder and transvestic fetishism remain in the Diagnostic and Statistical Manual of Mental Disorders IV.
In a survey with over 300 lesbian, bisexual and gay adolescents, Savin-Williams reported that the more one was open about their sexual orientation, the better their self-esteem was. But is it a causal relationship? And if so, which is the chicken and which is the egg? Among sociologists, the common belief is that by coming out, gays and lesbians develop a better sense of self, whereas psychological research shows that people with better self-esteem and support systems are more likely to come out. Savin-Williams also found that lesbians, gays, and bisexuals from urban areas tend to be out much more frequently than those in rural areas.