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All About Sexual Orientation

Few areas of psychology have been as controversial as the study of sexual orientation. What percentage of people are gay, and what is the most appropriate criterion for terming someone gay? Why are some men and woman attracted primarily to same-sex partners? Is it simply a matter of choice? Is sexual orientation determined by biology, by social experience, or by early learning?

Research in recent years has provided at least some answers, and some provocative new theories. First of all, we know that the percentage of gay people in the American population depends heavily on what criterion we use. If we use self-definitions — that is, if we ask what percentage of people label themselves as gay, lesbian, or bisexual, the percentage is a little over 2 percent (2.8 percent of men and 1.4 percent of women). If we adopt a looser definition and ask what percentage of people either have had consensual adult homosexual experiences or are currently attracted mainly to members of their own sex, that percentage rises to about 9 percent (about the same percentage of people who are left-handed).

Nature or Nurture?

The question of “cause” is a bit more complicated. We know from survey studies that early theories that emphasized factors like pathological parent-child interactions or the effect of early sexual encounters have found little, if any, support. No significant differences in parent behavior or tendencies to “identify” with the opposite sex parent have proven to be associated with sexual orientation. Furthermore, most gay men and lesbians report having felt attracted to members of their own sex long before they acted on those feelings or had sexual experiences with either same-sex or opposite-sex partners. Clearly, it was not the experience of satisfying, unsatisfying, or traumatic early sexual experiences that dictated the later sexual orientations of these individuals.

Because “nurture” explanations have proven to be inadequate, some psychologists have offered theories that emphasized “nature,” that is, genetic or biological factors. Studies of siblings, including twins, provide one line of evidence for the role of genes. For example, identical twins are more likely to show the same sexual orientation than fraternal (non-identical) twins. At the same time, it is important to note that even among identical twins, whose genetic make-up is presumably identical, approximately fifty percent of the time the identical twin of a gay man or lesbian is heterosexual. So biology obviously isn’t the whole answer. Experience does seem to play at least some role.

The strongest finding from survey research on the topic involves the association between adult homosexuality and reports of “gender nonconformity” in childhood. That is, we know from a great deal of evidence that, as children, gay men and lesbians were less likely than heterosexuals to have enjoyed sex-typical activities (for example rough-and-tumble games for boys, doll play or jacks for girls) and more likely to have enjoyed sex-atypical activities. Gay men and lesbians were also more likely to have had opposite-sex playmates. The data in question are impressive. In the case of both gay men and lesbians, it is dislike for “own-sex” activities that is most notable. In a 1981 Kinsey Institute survey of more than 1000 homosexual and 500 heterosexual men and women living in the San Francisco Bay area, 63 percent of both gay men and lesbians reported that they had not enjoyed activities typical of their sex during their childhood years, compared with only 10 percent and 15 percent of heterosexual men and women, respectively.

These data, it should be emphasized, do not show that all gay men played with dolls and all lesbians played with trucks. Nor do they show that all boys who played with dolls became gay men or that all tomboys became gay women; in fact, a majority of both lesbians and heterosexual women enjoyed boys’ activities during childhood. But the association between childhood play preference and adult sexuality seems strong enough to merit some explanation. Many sexuality researchers believe that playmate and activity preferences are early signs of whatever genetic or biological characteristics will be expressed in later sexual preferences. In other words, these researchers imply that there is a direct link between biological makeup and sexual orientation, although they recognize that the relationship is not perfect one, and that other factors play a role.

All About Sexual Orientation

Ben Martin, Psy.D.

Ben Martin, Psy.D. is a clinical psychologist in private practice. He also writes psychoeducational articles about mental disorders and mental illness.

APA Reference
Martin, B. (2020). All About Sexual Orientation. Psych Central. Retrieved on August 4, 2020, from
Scientifically Reviewed
Last updated: 14 Jan 2020 (Originally: 17 May 2016)
Last reviewed: By a member of our scientific advisory board on 14 Jan 2020
Published on Psych All rights reserved.