Last modified on May 12, 2021, at 22:50

Homosexuality and Genetics

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Eight major studies of identical twins in the United States, Australia and Scandinavia during the last two decades indicate that homosexuals were not born that way.[1]

In short, concerning homosexuality and genetics, science has yet to find a link in terms of it being a cause of homosexuality, although a common argument is that an inclination to homosexuality is inborn and immutable. It is widely believed that the public will become more accepting of homosexuality if they are convinced that it is inborn and immutable. For example, neuroscientist and homosexual Simon Levay stated: "...people who think that gays and lesbians are born that way are also more likely to support gay rights."[2] However, a genetic basis to homosexual desire does not prevent homosexuals from choosing not to participate in homosexual activities.

When asked if homosexuality was rooted solely in biology, gay gene researcher, Dean Hamer, replied, "Absolutely not. From twin studies, we already know that half or more of the variability in sexual orientation is not inherited. Our studies try to pinpoint the genetic factors...not negate the psychosocial factors" (Anastasia, 1995, p. 43).[3]
No professional scientist in the last 40 years has even claimed to have found any evidence that queerness is always genetic in all cases. Even the highly publicized identical twin studies by Michael Bailey and Richard Pillard, which were so often touted as evidence for a "gay gene," never found that any more than 52% of the identical twins of queer people were queer. The other 48% of identical twins of queer men were not queer. This leaves at least 48% of the queer community unaccounted for by genetic theories.[Citation Needed]

Science has found no definitive link as far as genetics being the ultimate arbiter of whether a person engages in homosexuality

See also: Failure of Experiments to Show Genetic Determinism For Homosexuality

Columbia University psychiatry professors Drs. William Byrne and Bruce Parsons stated: "There is no evidence that at present to substantiate a biological theory. [T]he appeal of current biological explanations for sexual orientation may derive more from dissatisfaction with the present status of psychosocial explanations than from a substantiating body of experimental data".

There is no scientific consensus favoring a genetic cause of homosexuality, and the American Psychological Association's assertion is merely that:

  • ...most scientists today agree that sexual orientation is most likely the result of a complex interaction of environmental, cognitive and biological factors.[4]

The emphasis is on environmental and cognitive factors, because these can be studied scientifically.

Concerned Women of America reports the following:

In May 2000, the American Psychiatric Association issued a Fact Sheet, "Gay, Lesbian and Bisexual Issues," which includes this statement:

"Currently, there is a renewed interest in searching for biological etiologies for homosexuality. However, to date there are no replicated scientific studies supporting any specific biological etiology for homosexuality."[5]

Research suggests that adoptive brothers are more likely to both be homosexuals than the biological brothers, who share half their genes. This data prompted the journal Science to report "this . . . suggests that there is no genetic component, but rather an environmental component shared in families".[6][7] However, in regards to psychosocial and biological theories in regards to the origin of homosexuality, Columbia University psychiatry professors Drs. William Byrne and Bruce Parsons stated in 1994: "There is no evidence that at present to substantiate a biological theory. [T]he appeal of current biological explanations for sexual orientation may derive more from dissatisfaction with the present status of psychosocial explanations than from a substantiating body of experimental data".[8]

Herbert Hendin wrote:

Anthropologists had observed that relatively uncompetitive primitive cultures such as those that do not distinguish or reward the best hunters in distinction to the other men in the tribe have virtually no homosexuality."[9]

Dr. Tahir I. Jaz, M.D., Winnipeg, Canada states: "The increasing claims of being "born that way" parallels the rising political activism of homosexual organisations, who politicise the issue of homosexual origins . In the 1970s, approximately ten percent of homosexuals claimed to be "born homosexual" according to a large scale survey....However, in a survey in the 1980s, with the homosexual rights movement increasingly becoming active, thirty-five percent claimed to be born that way.[10]

Dr. Dean Hamer is a researcher often cited to argue that there is empirical data supporting the notion that homosexuality is genetic in origin. News organizations like National Public Radio and Newsweek have done news stories regarding his work.[11] The statements like "the studies are objective and sound...there is no room for doubt that homosexuality is highly heritable" popped up and the T-shirts sold in gay and lesbian bookstores in the mid-1990s declared: "Xq28 - Thanks for the genes mom".[12] However, in regards to the press trumpeting various findings genetics-of-behavior research uncritically the science journal Science stated the following in 1994:

Time and time again, scientists have claimed that particular genes or chromosomal regions are associated with behavioral traits, only to withdraw their findings when they were not replicated. "Unfortunately," says Yale's [Dr. Joel] Gelernter, "it's hard to come up with many" findings linking specific genes to complex human behaviors that have been replicated. "...All were announced with great fanfare; all were greeted unskeptically in the popular press; all are now in disrepute."[13]
Martin A. Silverman, M.D. wrote regarding a famous study of Dr. Dean Hamer:
On July 16, 1993, it was reported in Science (pp. 291, 321) that geneticist Dean Hamer and his team at the National Cancer Institute had reported on a study involving 40 pairs of brothers both of whom were gay that had led them to conclude that they had discovered a factor on the X chromosome through which gayness was genetically transmitted to them from their mothers. This was hailed as proof that homosexuality in men is biological in origin. Two years later, however, Eliot Marshall reported in Science (June 30, 1995, p.268) George Ebers and George Rice of the University of Western Ontario had unsuccessfully attempted to replicate Hamer's findings and had "found no evidence that gayness is passed from mother to son" genetically. He also reported that the Office of Research Integrity in the Department of Health and Human Services was investigating Hamer's work.[14]

The research team, led by Dr George Rice of Canada's University of Western Ontario, performed one of the biggest studies to date investigating whether there is a genetic cause of homosexuality and has failed to find any evidence for the existence of a so-called ‘gay gene’.[15] For theories on genetic origin of homosexuality to be fact, however, there should never be a case when one male identical twin is heterosexual and one is homosexual. It's genetically impossible since both male identical twins share 100 percent of the same genes. If sexual behavior is genetic, then both identical twins will always be either heterosexual or homosexual. The findings however discredit such hypothesis and show that non-genetic factors play a significant part in shaping sexual preference.[16]

Homosexual behavior is voluntary and subject to control by the human will, just as heterosexual behavior is. Sex and intimacy, though, are basic necessities of human life, and acting on them, whether they be heterosexual or homosexual, is natural.

Homosexuality and genetic mutations

See also: Homosexuality and genetic mutations

Left-handedness is a good indicator of a high mutational load.[17] People who are left-handed higher incidences of autism and schizophrenia.[18]

In 2000, The journal the Psychological Bulletin published an article entitled Sexual orientation and handedness in men and women: a meta-analysis and the abstract for the journal article declared:

The authors conducted a meta-analysis of 20 studies that compared the rates of non-right-handedness in 6,987 homosexual (6,182 men and 805 women) and 16,423 heterosexual (14,808 men and 1,615 women) participants. Homosexual participants had 39% greater odds of being non-right-handed. The corresponding values for homosexual men (20 contrasts) and women (9 contrasts) were 34% and 91%, respectively.[19]

Dr. Neil Whitehead writes about left-handedness and homosexuality:

Using their results it is possible to derive a number, which shows the extent of any link there may be. Here's how it's done. Given that 2.7% of adult Western males are homosexuals and 1.7% of adult Western women female homosexuals, (both figures including bisexuals) and defined as activity in the last 12 months3 we can calculate by standard methods that only 3.9% of left-handed males are homosexual and only 3.3% of left-handed females are lesbian.

In other words the overwhelming majority of those who are left-handed when young do not become homosexual. The strength of any underlying factor producing both is weak. Something unusual happens to a small number of left-handed people and their sexual-orientation development is atypical.

What might that be? Are there alternative psychological explanations of the effect described in the paper?

I suggest at least one - everyone knows that left-handed people feel in a minority, and different. Very many homosexual people attest to feeling different and not belonging when they were growing up. Left-handedness could increase feelings of difference and be one important factor in the complex leading to homosexuality. This could apply to both men and women and the authors quote a study in which non-right-handed women rated themselves as less feminine. Additionally feeding into this could be altered brain hemisphere dominance and the psychological effects of atypical gender-specific skills.


Most left-handed children do not become homosexual. Conversely and importantly, most homosexual people are not left-handed. So the main routes to homosexuality are not via whatever causes being left-handed. There is a link or correlation to homosexuality but it is weak.[20]

The causes of homosexuality in individuals suggests that a person's free will is the ultimate arbiter of whether someone chooses to be a homosexual (see: Homosexuality and choice and Homosexuality and genetics and Ex-homosexuals).

Genetics, Evolutionary Paradigm, and Creation Science

For more information please see: Genetics, Homosexuality, Evolutionary Paradigm, and Creation Science

In 1993, Professor Miron Baron, M.D., the renowned medical researcher and Professor at Columbia University, wrote in BMJ (British Medical Journal) that there is a conflict relative to the theory of evolution and the notion of genetic determinism concerning homosexuality. Dr. Baron wrote "...from an evolutionary perspective, genetically determined homosexuality would have become extinct long ago because of reduced reproduction."[21] In the United States, liberals are more likely to believe in the theory of evolution.[22] Also, in the United States, twice as many liberals as conservatives (46% versus 22%) believe people are born homosexual and liberals generally have more favorable opinions about homosexuality.[23] Given Dr. Miron Baron's commentary about homosexuality, American liberals are inconsistent on the issues of evolution and homosexuality.

An individual's beliefs regarding creation science/creationism and the theory of evolution appear to influence their views on homosexuality. Creationist scientists and creationist assert that the theory of evolution cannot account for the origin of gender and sexual reproduction.[24][25] Creation Ministries International states: "Homosexual acts go against God’s original design of a man and a woman becoming one flesh — see Genesis 1 and 2, endorsed by Jesus Himself in Matthew 19:3–6."[26] In addition, the vast majority of creation scientists reject the notion of genetic determinism concerning the origin of homosexuality.[27]

See also

External links


  1. Identical Twin Studies Prove Homosexuality is Not Genetic
  3. Homosexuality 101: What Every Therapist, Parent, And Homosexual Should Know - Julie Harren, Ph.D., LMFT
  6. (Science, Vol. 262, page 2063, December 24, 1993)
  9. "Kardiner and Linton, in a psychoanalytic anthropological study of Tanala, examined homosexuality in the context of the entire Tanalese culture (1939). They showed that a dramatic rise in homosexuality when social and economic forces inflamed competitiveness was one of several manifestations of frustrated rage (crime was another) among young men who were having particular difficulty with the pressures the culture was exerting on them. Homosexuality: The Psychosocial Dimension - Journal of American Academy of Psychoanalysis, 6:479-496(1978)
  12. Matt Ridley (2000). Genome. Fourth Estate Ltd.. ISBN 978-1857-028355. 
  13. Mann, C. Genes and behavior. Science 264:1687 (1994)
  15. No evidence for ‘homosexual gene’. Retrieved on September 27, 2013. “One of the biggest studies to date investigating whether there is a genetic cause of homosexuality has failed to find any evidence for the existence of a so-called ‘gay gene’. The research team, led by Dr George Rice of Canada’s University of Western Ontario, initiated the study. It followed the earlier sensational claims of self-confessed homosexual Dr Dean Hamer and his team in 1993 purporting to have found a genetic link to homosexuality. Several years of frenzied research aimed at isolating the ‘homosexual gene’ proved fruitless. Now Dr Rice’s team, using a much larger study sample and sophisticated genetic tests, has found no evidence at all of any link between this marker and sexual orientation. The Independent, (U.K.), April 23, 1999, p. 5; Science, April 23, 1999, pp. 571, 665–667.”
  16. Jeff Olson (1996). When Passions Are Confused. RBC Ministries,, 6–7. 
  18. Atheists are more likely to be left handed, study finds, The Telegraph, 2017
  19. Sexual orientation and handedness in men and women: a meta-analysis by Lalumière ML1, Blanchard R, Zucker KJ., Psychol Bull. 2000 Jul;126(4):575-92.
  20. Is left-handedness linked to homosexuality? by Dr. Neil Whitehead
  21. BMJ. 1993 August 7; 307(6900): 337–338.