Biological Foundation of Homosexuality Essay Sample
Homosexuality is considered to be deviant behavior in modern society. There is little doubt that in ancient times, people engage in same-sex relationships, but there is little evidence that these people engage in same-sex relationship exclusively. With the rise of Christianity, the view that homosexuality is a sinful act began to reassert itself. Though there is discrimination against homosexuals, they began forming communities fighting to be accepted into the society. Many researchers engaged in the psychology of homosexuality. In the meantime, personality, parental care and environmental factors are the more accepted cause of homosexuality. Researches for the biological foundation of homosexuality has still a very long way to go in proving that homosexuality is something predestined, encoded in one’s genetic make-up, and not a matter of choice.
Scientists, for a long time, had held that there is what they call a “Darwinian paradox” to homosexuality, not merely because it “is evolutionary maladaptive… but because any genetic tendency to avoid heterosexual opportunities should have been selected out long ago” (Pinker). There is a difficulty to explain of “how genetic factors that lower male fecundity survive natural selection” (Camperio-Ciani 2217). Steven Pinker, in his article “Sniffing out the gay gene,” suggests that “gay genes” must have some advantages when carried by female, or that it may be biological but not particularly genetic.
It is important to note that homosexual behaviors had been observed in the natural world, not only among humans. Researches, however, are indecisive whether these behaviors are genetic or not. On the other hand, scientists agree that these behaviors serve some purpose advantageous to the particular species.
The genetic foundations of homosexuality have been popular since the past century. It is unfortunate that there are little evidences that link homosexuality as genetically inherited, and the little evidences prove to be non circumstantial, at least among humans.
In 1991, a research conducted by Simon LeVay found that a tiny region in the hypothalamus “of homosexual men was more like that in women than in heterosexual men” (Gorman). LeVay’s research, however, had many flaws as he himself admits. The subject of his study included, but not all, both homosexual and heterosexual men and women who died of AIDS and the difference in size in the hypothalamus, particularly the INAH 3, of homosexual and heterosexual males could be caused by the disease. Seventeen percent, a statistically significant number, of LeVay’s test subjects have also contradicted his theory. It may also be concluded that the difference was the result of homosexuality, rather than the cause. “Scientific studies have indicated that behavior itself might cause the size of the neurons to fluctuate” (Ankerberg). Furthermore, there has been no scientific evidence that the INAH 3, although associated with emotions and sexuality, has something to do with sexual orientation.
Michael Bailey and Richard Pillard also studied homosexuality the same year, using identical twins to prove or disprove its genetic foundation. They also included fraternal twins, non-twin brothers, and adopted brothers for comparison. Their study found that 52% of the identical-twin test subjects turn out to be both homosexuals, while only 22% of the fraternal twins, 9% of non-twin brothers and 11% of adopted brothers are both homosexuals. Bailey and Pillar concluded that the “high percentage of homosexuality among identical twins was because of their identical genetic make-up” (Ankerberg). This conclusion, however, was also refuted, stating that the implication of the genetic factor has no basis. Richard Cohen explains that “as identical twins have identical genetic make-up, it is much easier to interpret the findings as supporting the nurture rather than the nature theory. If homosexual orientation is genetic, then 100% of all identical twin brothers should have been homosexual, but only half were. Therefore, it is easy to conclude that environmental factors, not genes, cause homosexuality” (Ankerberg). Even LeVay has commented that the twin studies “suggests that it’s (homosexuality) not totally inborn because even identical twins are not always of the same sexual orientation” (Ankerberg).
Aside from the flaws of the method, hypotheses and conclusions by LeVay, Bailey and Pillard, their researches have proven to be “biased.” Both LeVay and Pillard are homosexuals themselves and has dedicated their research to promote “the idea that homosexuality is a matter of destiny, not choice… that [it] is inborn and therefore a natural sexual behavior” (Ankerberg). These flaws seem to be inadmissible in the scientific world. Although the studies suggest that there may be some genetic link for homosexuality, the results prove to be inconclusive. Few scientists had seriously conducted researches on the genetic foundation of homosexuality. After the failures of researches, Masters and Johnson stated that “the genetic theory of homosexuality has been generally discarded” (Ankerberg). The researches, however, did not end.
In 1993, a study conducted by Hamer, et al., “have shown an elevated homosexuality rate in the maternal line of homosexuals” using pedigree analysis (Camperio-Ciani 2217). This means that there is a high rate of homosexuality among the mother-side relatives of another homosexual. The study suggested an X-linked genetic factor for homosexuality. They have identified the candidate factor on Xq28 region. Camperio-Ciani, however, explained that “these findings… have been difficult to replicate” (p. 2217).
A separate study conducted by Blanchard found that “homosexual orientation correlates with late-birth order and an excess of older brothers” (Camperio-Ciani 2217) that was not found with older sisters or younger siblings. It suggested that “each additional older brother increases the odds of homosexuality in the next male born by 33%” (Camperio-Ciani 2217). Blanchard hypothesized that late birth order and sibling sex ratio reflected progressive immunization of the H-Y antigen produced by male fetuses. He argues that a number of male pregnancies must have reduced the the sexual differentiation of the brain in succeeding male fetuses.
A study conducted by Camperio-Ciani, et al., shows that the data they have gathered “contradict a number of hypotheses about genetic basis of homosexuality” (p. 2217). They investigated the hypotheses offered by Hamer and Blanchard and found that the maternal and birth order variables have only limited effect, generating only 14% result from maternal effect and 6.7% from late-birth order effect. What was interesting, however, was that they had found that “maternal relatives of homosexuals have higher fecundity than maternal relatives of heterosexuals” which were not found in the paternal line (p. 2219). This supports the suggestion that there must be X-linked genetic factors for homosexuality. The data, however, revealed that the X-linked allele that substantially enhances female fecundity is common in maternal relatives of homosexuals while homosexuality, although might appear rarely, remains uncommon. Camperio-Ciani concludes that the result of their study is more consistent with the theoretical and empirical studies which show that individual experiences are more powerful determinant of human sexual behavior and self-identity. Although, it is stll possible for a higher incidence of homosexuality in the maternal line, it is more likely a result of “culturally, rather than genetically, inherited traits” (Camperio-Ciani 2220).
Another study conducted by a team of Swedish neuroscientists showed that a part of the hypothalamus of heterosexual female and homosexual male responded to testosterone derivative found in men, suggesting that the brain of homosexual males must have similarities with that of heterosexual females. However, Pinker held that “the difference in the brain responses of gay and straight men does not, by itself, prove that homosexuality is innate.” He explains that “learned inclinations, like innate ones, must reside somewhere in the brain,” hinting that homosexuality may be “learned” and which men may choose to be.
In summary, various researches have been conducted to find the genetic foundation of homosexuality. Pinker explains that “some gay groups condemn such research because it could stigmatize gay people as defective and lead to day in which parents could selectively abort hildren with ‘gay genes.’ Others welcome the research because it shows that people don’t ‘choose’ to be gay and hence can’t be criticized for it.” Up to the present time, no research has substantially linked homosexuality with genetics. Dr. John Money of John Hopkins University stated that “no chromosomal differences have been found between homosexual subjects and heterosexual controls… On the basis of our present knowledge, there is no basis on which to justify an (sic) hypothesis that homosexuals or bisexuals of any degree or type are chromosomally discrepant… from heterosexuals” (Ankerberg).
Establishing the biological foundation of homosexuality would, once and for all, answer the question of whether homosexuals choose to be the way they are or whether they were born as such. If homosexuality is genetically inherited, it does not mean that it is an evolutionary error, rather, it must have some advantages to survive natural selection.
The failure to link homosexuality with genetics does not mean that homosexuals are altogether undesirable. Pinker held that “what is evolutionary adaptive and what is morally justifiable have little to do with each other.” Perhaps it is better to abandon the endeavor and just accept the psychology behind homosexuality, which is, after all, the more acceptable justification.
Ankerberg, John F. “What ’causes’ homosexuality?” Ankerberg Theological Research Institute. 17 July 2008. <www.ankerberg.org/Articles/_PDFArchives/streams-of-life/SL2W0703.pdf>
Camperio-Ciani, Andrea, Corna, Francesca and Claudio Capiluppi. “Evidence for maternally inherited factors favouring male homosexuality and promoting female fecundity.” Proceedings of the Royal Society Biological Science v.271-1554 (2004): 2217-2221.
Gorman, Christine. “Are gay men born that way?” 9 September 1999. TIME. 16 July 2008. <http://www.time.com/time/magazine/article/0,9171,973763-1,00.html>
Pinker, Steven. “Sniffing out the gay gene.” 17 May 2005. New York Times. 16 July 2008. <http://www.nytimes.com/2005/05/17/opinion/17pinker.html>