Hockenbury Discovering Psychology 5th txtbk

Human Sexuality337Many people who consider themselves heterosexual have had a homosexual experienceat some point in their lives. In the same vein, many homosexuals have had heterosexualexperiences (Rieger & others, 2005). Other people, like our friend Richardin the chapter Prologue, consider themselves to be homosexual but have had heterosexualrelationships. The key point is that there is not always a perfect correspondencebetween a particular person’s sexual identity, sexual desires, and sexual behaviors.Determining the number of people who are homosexual or heterosexual is problematicfor several reasons (see Savin-Williams, 2008). First, survey results vary dependingon how the researchers define the terms homosexual, heterosexual, and bisexual.Second, gays and lesbians are not distributed evenly throughout the population.In rural areas and small towns, gays, lesbians, and bisexuals make up about 1 percentof the population. But in the largest U.S. cities, approximately 1 of 8 people (or 12percent) consider themselves gay, lesbian, or bisexual (Michael & others, 1994). Estimatesof the size of the gay and lesbian population can vary, depending on:• How researchers structure survey questions• How they define the criteria for inclusion in gay, lesbian, or bisexual categories• Where the survey is conducted• How survey participants are selectedDepending upon how sexual orientation is defined, estimates of the prevalancerate of homosexuality in the general population ranges from 1 percent to 21 percent(Savin-Williams, 2006). More important than the exact number of gays andlesbians is the recognition that gays and lesbians constitute a significant segment ofthe adult population in the United States. According to the most reasonable estimates,it’s safe to say that between 7 million and 15 million American men andwomen are gay or lesbian.What Determines Sexual Orientation?Despite considerable research on this question, psychologists and other researcherscannot say with certainty why people become homosexual or bisexual. For that matter,psychologists don’t know exactly why people become heterosexual either. Still,research on sexual orientation has pointed toward several general conclusions, especiallywith regard to homosexuality.Evidence from multiple studies shows that genetics plays a role in determiningsexual orientation (Bailey & others, 2000). For example, psychologists MichaelBailey and Richard Pillard (1991) compared the incidence of male homosexualityamong pairs of identical twins (who have identical genes), fraternal twins (who aregenetically as similar as any two non-twin siblings), and adoptive brothers (whohave no common genetic heritage but share the same upbringing). The researchersfound that the closer the degree of genetic relationship, the more likely it was thatwhen one brother was homosexual, the other brother would also be homosexual.Specifically, both brothers were homosexual in 52 percent of the identical twins, 22percent of the fraternal twins, and 11 percent of the adoptive brothers.Bailey and his colleagues (1993) discovered very similar results in twin studies oflesbians. In 48 percent of identical twins and 16 percent of fraternal twins, when onesister was lesbian, so was the other sister, compared with only 6 percent of adoptivesisters. However, since the identical twins were both homosexual in only half of thetwin pairs, it’s clear that genetic predisposition alone cannot explain sexual orientation.In the largest twin study to date, Swedish researchers showed that both geneticand nonshared environmental factors were involved in sexual orientation (Långström& others, 2008). What are “nonshared” environmental factors? Influences that areexperienced by one, but not both, twins. More specifically, these are social and bio -logical factors, rather than upbringing or family environment.These studies and others support the notion that sexual orientation is at leastpartly influenced by genetics (Hyde, 2005). However, that genetic influence is likelyto be complex, involving the interaction of multiple genes, not a single “gay gene”U.S. Congressman Barney Frank: “YouCan’t Make Yourself a Different Person.”One of the first openly gay politicians, Frankhas been a member of the U.S. Congresssince 1981. Frank first realized he was gay inhis early teenage years. When asked if heterosexualitywas ever an option for him,Frank (1996) responded, “I wished it was.But it wasn’t. I can’t imagine that anybodybelieves that a 13-year-old in 1953 thinks,‘Boy, it would really be great to be part ofthis minority that everybody hates and tohave a really restricted life.’ You can’t makeyourself a different person. I am who I am. Ihave no idea why.”