Is Sexual Orientation Genetically Determined? (Part 1)

Are people born gay?  Can sexual orientation be changed?  How should the Christian church respond to the challenges of ministering to those with same-sex attraction?  The first part of this article will discuss whether or not homosexual orientation is genetically determined and the second part will discuss where same-sex attraction comes from and if it is possible for that orientation to be changed.

While many assume that people are “born gay” or are gay as a result of a “gay gene,” there is absolutely no proof that homosexuality is determined by genetics (Stanton and Maier, Marriage on Trial, 133).  The first major study to try to find a biological cause for homosexuality is Simon LeVay’s study comparing the hypothalamuses of several gay men who died of AIDS with “sixteen presumed heterosexual men, six of whom died of AIDS” (Welch, Blame It on the Brain?, 166).  However, even LeVay has admitted that his study does not prove homosexuality is biologically determined: “I did not prove that homosexuality is genetic, or find a genetic cause for being gay.  I didn’t show that gay men are born that way, the most common mistake people make in interpreting my work” (Cited in Staver, Same-Sex Marriage, 77).  There are several problems with LeVay’s study which include too small a sample size, the impact of AIDS or AIDS medication on the brain, three homosexual brains were no different from that of the heterosexuals, and the differences may have been the result of homosexual practice as LeVay has admitted (Welch, 166).   Because six of the sixteen men who were assumed to be heterosexual died of AIDS, it is unlikely that they all were heterosexual (Gagnon, The Bible and Homosexual Practice, 397).  A later “more careful (blind) study by William Byne did not find a difference between male homosexual and male heterosexual INAH3s” (Gagnon, 398).

A later study by Michael Bailey and Richard Pillard studied the frequency of homosexuality among identical twins when one twin is gay to see if there is a genetic cause to homosexuality.  They found that when one identical twin is gay there is a higher statistical probability that the other one will be too (Stanton and Maier, 134).  But rather than proving that homosexuality is genetically determined, it actually proves the opposite.  As Robert Gagnon explains, “If homosexuality were determined completely by the genes, we would expect the concordance rate in such cases to be 100%” (Gagnon, 403).  When one identical twin is gay, the other twin would always be gay because they both have the same genes.  But this is not the case.  The higher rates of homosexuality among identical twins when one twin is gay is likely because “identical twins typically have a profound influence on each other” (Welch, 168).  This would “explain why adoptive brothers of homosexuals would be four times more likely than the general population to be homosexual” (Gagnon, 406).

Another study used to support a biological basis for homosexuality is Dean Hamer’s study of the genetic material of gay brothers who are nonidentical twins (Stanton and Maier, 134).  Glenn T. Stanton and Bill Maier explain why Hamer’s study does not support the contention that homosexuality is genetically determined: “Hamer’s study actually found several gay men who did not have the genetic marker that supposedly contributed to homosexuality.  He also found several men who had the marker but were not gay. Perhaps even more significantly, other researchers have been unable to replicate the results of any of these studies” (135).  Hamer himself says concerning whether his study proves homosexuality is genetically determined: “Absolutely not.  From twin studies, we already know that half or more of the variability in sexual orientation is not inherited. . . . The best recent study suggests that female sexual identification is more a matter of environment than heredity” (Cited in Staver, Same-Sex Marriage, 77).

As Stanton and Maier conclude: “LeVay, Bailey and Pillard, and Hamer have all stated that their studies did not prove that homosexuality is genetically or biologically determined” (Stanton and Maier, 135).  It is therefore rather disingenuous for advocates of gay marriage to argue that science has proved homosexuality is genetically determined when it has proved no such thing.  But if homosexuality is not biologically determined, then what causes homosexuality?  While the reasons for homosexual orientation are not the same in every case, Richard Fitzgibbons lists some of the most important factors that scientists have given: “Weak masculine identity . . . a poor emotional relationship with the father . . . poor body image . . . sexual abuse by older, more powerful children or by adults . . . mistrust of women’s love . . . the pursuit of pleasure” (Richard Fitzgibbons, “The Origins and Therapy of Same-Sex Attraction Disorder,” 88-89).

As Gagnon notes, some homosexual orientation is the result of sexual abuse: “homosexuals and bisexuals are three to nine times more likely to have experienced sex as a child (usually with an adolescent or adult male) than their heterosexual counterparts” (Gagnon, 412).  The Archives of Sexual Behavior reports that “46 percent of homosexual men and 22 percent of homosexual women reported having been molested by a person of the same gender” (Cited in Peter Sprigg and Timothy Dailey, Getting It Straight: What the Research Shows About Homosexuality, 140).  After his study on the subject, David Finkelhor concludes that “boys victimized by older men were over four times more likely to be currently engaged in homosexual activity than were non-victims” (141).

It is also evident that homosexual orientation is not an immutable characteristic on the basis of studies of the sexual history of homosexuals.  Gagnon reports that “Greater than 9 out of every 10 Americans (90.7% of all men and 94.9% of women) who have had any same-gender sex since puberty have also had opposite-gender sex” (Gagnon, 419).  Peter Sprigg and Timothy Dailey report that “only about one in every 15 men with homosexual experience has been exclusively homosexual in behavior, while only about one in every 21 women with homosexual experience has been exclusively homosexual” (Sprigg and Dailey, 49).  That sexual orientation is greatly influenced by the environment in which a child grows up in is evidenced by the fact that “12 percent of the children of lesbians became active lesbians themselves, a rate which is at least four times the base rate of lesbianism in the adult female population” (Sprigg and Dailey, 110).  These findings should forever put to rest the theory that homosexual orientation is genetically determined.

The California Supreme Court has a compelling state interest in not allowing gay marriage because the societal acceptance of homosexuality will only lead to higher rates of homosexuality and all of the health problems that come with it.  The life expectancy of male homosexuals is anywhere between 8 to 20 years less than that of male heterosexuals (Gagnon, 472).  Stanton and Maier report that “homosexuals are more likely to suffer from mental illness, alcohol and substance abuse, and a variety of life-threatening diseases such as AIDS, certain types of cancer, and hepatitis. . . . on average, male homosexuals die a premature death by up to twenty years. . . . both gays and lesbians are more likely than heterosexuals to commit suicide, and to be victims of domestic violence at the hands of a sex partner” (Stanton and Maier, 142).

According to Gagnon, the negative effects of acceptance of homosexuality as a society include: “An increase in serious health problems . . . an increase in the incidence of same-sex pedophilic and adult-adolescent sexual activity . . . a further cheapening of the institutions of marriage and family . . . the annihilation of all societal gender norms . . . the public, political, educational, professional, and legal marginalization of any (both organizational and individuals) who make known their opposition to homosexual behavior, as the societal equivalent of racists” (Gagnon, 488).  Gagnon is exactly right that once homosexual orientation is viewed as being in the same category as skin color, those who disagree with homosexuality must be viewed no differently than racists because both sexual orientation and skin color are now fundamentally the same.


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