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Homosexuality – Genetic or Acquired?

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Homosexuality - Genetic or Acquired?

A debate is going on in our country on same-sex marriages and homosexuality. There is an attempt by some groups with vested social, political and legal interests to create an impression in the public mind that homosexuals are ‘born that way’ or that God has made them that way. The underlying intention is to insist that they must be accepted without any question. I must clarify that in this article; I do not wish to comment on the issue of social and legal acceptance of homosexuality. However, I will show that the argument of ‘born that way’ is scientifically wrong. There is no genetic basis for homosexuality; it is an acquired preference or orientation. There could be several environmental and/or hormonal reasons why some people become homosexuals but there is no ‘genetic wiring’ that ‘compels’ them to become homosexuals.

Are homosexuals ‘born gay?

For long, many homosexuals have been trying to tell the world that their sexual orientation, far from being a personal choice or lifestyle (as it is often called), is something neither chosen nor changeable. In fact, the very term ‘sexual orientation’ was introduced in the 1980s as a result of their contrived attempts to suggest that homosexuality was a biological compulsion. Earlier, the term ‘sexual preference’ was used, which indicated that it was a matter of choice.  

In 1993, Science published a study by Dean Hamer et al of the US National Institutes of Health that found in 40 pairs of siblings a relationship between male homosexuality and a certain region of the X sex chromosome called Xq28. Supporters of homosexuals in the media jumped over it with joy and termed it the ‘gay gene’. However, further research failed to replicate this presumed finding. In 1999, another study in the same journal concluded, “These results do not support an X-linked gene underlying male homosexuality” and the journal published a sort of apology also.

‘Gay Gene’ – a hoax

Molecular genetic techniques provide for sophisticated analysis, employing genetic markers available on all chromosomes, across all regions of the human genome. One method of using genetic markers is to study the association between the markers and the trait of interest across the population as a whole.

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At this juncture, I must caution the readers that all these research papers are extremely complex and unintelligible to journalists or the lay reader. As a result, reporting on them in the media is often outrageously erroneous. I have processed them with great care and sagacity to present their results in an understandable form.

The first study was in 2012 by a team of eight scientists led by E. M. Drabant of the California-based personal genomics and biotechnology company called 23andMe. They found no significant genetic associations for male homosexuality. The second study was in 2017 by a team of 14 scientists led by Alan Sanders of North Shore University, Illinois. This study was also on males only and used a technique called Affymetrix single nucleotide polymorphism (SNP) arrays. They found that no SNP reached genome-wide significance.

The third and hitherto the largest research of its kind was published in 2019 by 20 scientists led by Andrea Ganna of the Broad Institute of MIT and Harvard, and several other institutions as well as the research team of 23andMe. This was the first study that included both males and females. The approach was essentially quite simple. They focused on answers to one question: whether someone ever had sex with a same-sex partner, even once. Then they tried to find out if they have any genetic commonality amongst them.

They analysed the genetic database of nearly half a million people (477,522). The sample was drawn from a large British database, the UK Biobank, which answered extensive health and behaviour questions between 2006 and 2010 when they were between the ages of 40 and 69. The researchers also used data from nearly 70,000 customers of the genetic testing service 23andMe, who were 51 years old on average.

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In genetics, a locus (plural loci) refers to a specific, fixed position on a chromosome where a particular gene or genetic marker is located. Each chromosome carries many genes, with each gene occupying a different position or locus. In humans, the total number of protein-coding genes in a complete set of 23 chromosomes is estimated at 19,000–20,000. A genetic marker is a gene or DNA sequence with a known location on a chromosome that can be used to identify individuals or species.

The researchers found just five single points (autosomal loci—an autosome is any chromosome that is not a sex chromosome) in the genome that seemed to be common among people who had had at least one same-sex experience (that is, were regarded as homosexual). But taken together, these five markers explained less than 1 per cent of the differences in sexual activity among people in the study. When the researchers looked at the overall genetic similarity of individuals who had had a same-sex experience, genetics seemed to account for between 8 and 25 per cent of the behaviour. The rest was presumably a result of environmental or other biological influences.

Most people in the media had gone to town with this 8 to 25% finding. What they could not understand and what the researchers themselves confirmed to OpenMind was that this meant that between 75% and 92% of homosexual behaviour does not depend on genetic components! In simple words, the finding dispels the notion that a single gene or handful of genes make a person prone to same-sex behaviour.

The analysis concludes that there are no specific genetic predictors either. The researchers clarified that the genetic variants identified “do not allow meaningful prediction of an individual’s sexual behaviour.” When scientists tried to use genetic markers to predict how people in unrelated data sets reported their sexual behaviour, it turned out to be ‘too little genetic information’ to allow such prediction.

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Unfortunately, media and groups with vested social and political interests went on to cherry-pick and ‘hijack’ selected parts of the paper to further their own agenda. Shortly after the publication of the paper, a company called Insolent AI launched an app called ‘How gay are you?’ which claimed to predict a person’s degree of homosexuality based on their genetic profile. The app provoked widespread consternation at its obvious stupidity and was withdrawn after geneticist Joseph Vitti of the Broad Institute—one of the institutions participating in the study—himself started a petition on change.org for its elimination.

It should not be misconstrued that for whatever they were worth, those five genetic markers related only to sexual behaviour. Interestingly, two of the above-mentioned five genetic markers sit close to genes linked to sex hormones and smell. Dr. Melinda Mills of Oxford noted that two of the five variants the team found were discovered only in males and one was discovered only in females. One of the male variants is related to the sense of smell, which is involved in sexual attraction. The other male variant is associated with male pattern balding and sits near genes involved in male sex determination.

Further, the research also suggested the genetics of same-sex sexual behaviour shares some correlation with genes involved in some mental health issues (like major depressive disorder or schizophrenia, and with traits like risk-taking, cannabis use, openness to experience and loneliness) and personality traits— however, the authors took pains to clarify that this overlap could simply reflect the stress of enduring societal prejudice.

In a remarkable display of professional ethics, even Dean Hamer, the scientist who had led the now discredited 1993 study about locating the ‘gay gene’, also frankly accepted after the publication of this research that there is no ‘gay gene.’

Nature would not allow an evolutionary disadvantage

The absence of a ‘gay gene’ can also be understood in another way. All organisms in nature, from the lowliest of the creatures to the biggest animals, are genetically wired with the primaeval desire to propagate their own genes and, concurrently, their species through sexual reproduction. Had this desire not been there, life itself would have perished. This means that all creatures are ‘genetically wired’ for heterosexual reproductive sex and that is how life is sustained in the evolutionary struggle. 

Now, if homosexuality also had to be ‘wired into the genes’, it would result in an evolutionary disadvantage to that species because homosexuals would not reproduce and propagate. Nature or evolution could not allow that sort of mistake to be committed purposefully. If at all some evidence of such genes is ever found, it will have to be dismissed as a mutation, alteration or error in the genetic processes.

No genetic hardwiring for rape

To illustrate the matter further, it has been argued by some that if some males were to be genetically hardwired for rape, it would offer them an evolutionary advantage in terms of the propagation of their genes. The argument runs like this. A male of a species can successively impregnate a very large number of females in a short period of time. However, the females can produce only a limited number of survivable offspring and that too with considerable difficulty marred by long gestation, problems of pregnancy, delivery and rearing, etc. Hence the females have to be choosy in from whom they get impregnated so that, in their perception, only genes better suited for survival are propagated.

Also Read: Matrimonial ad for gay son stirs lively debate

This leads to competition amongst males and many of them have to necessarily remain sexually frustrated. Theoretically, if the means of access to legitimate, consenting sex are not available, then that male may be faced with the choice between using force for sex or genetic extinction.

Randy Thornhill and Craig T. Palmer, in their book ‘A Natural History of Rape: Biological Bases of Sexual Coercion’ argue that rape is a direct adaptation or outcome of natural selection that enables sexually disenfranchised men to procreate. They say that evolutionary psychology renders all men ‘potential rapists’. In the view of such sociobiological theories of rape, human rape appears not as an aberration but as an alternative gene-promotion strategy that is most likely to be adopted by the ‘losers’ in the competitive, harem-building struggle. However, observations in the animal kingdom do not lend support to this theory of males ‘born that way’ or ‘born rapists’. Rape is extremely rare in the animal kingdom.

Now, if Mother Nature did not wire males for rape even as it could have offered an evolutionary advantage, there is no reason that it would have wired them for homosexuality, which would result in a clear evolutionary disadvantage. 

Societal implications of such research

Several scientists who are part of the LGBTQ community said they were worried the findings could give ammunition to people who seek to use science to bolster biases and discrimination against gay people. Joseph Vitti wrote that they are afraid that the evidence that genes play only a partial role could embolden people who insist being gay is a choice and who advocate tactics like conversion therapy. In fact, Steven Reilly, a geneticist and postdoctoral researcher who is on the steering committee of the institute’s LGBTQ affinity group, said that he was against publishing the study.

The moment the study was published online, the Broad Institute took the unusual step of posting essays by Dr Reilly and others who raised questions about the ethics, science and social implications of the project. Quite unusual for a scientific project, the researchers even engaged with different LGBTQIA+ (lesbian, gay, bisexual, transgender, queer, intersex, asexual, and other+) and science communication organizations and created multimedia materials for a lay audience to communicate the results of the study to the broader audience. It is a different thing that those who normally do not read anything more than a newspaper article remained ignorant as ever.

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Dr N C Asthana IPS (Retd)
Dr N C Asthana IPS (Retd)
Dr. N. C. Asthana, IPS (Retd) is a former DGP of Kerala and ADG BSF/CRPF. Of the 51 books that he has authored, 20 are on terrorism, counter-terrorism, defense, strategic studies, military science, and internal security, etc. They have been reviewed at very high levels in the world and are regularly cited for authority in the research works at some of the most prestigious professional institutions of the world such as the US Army Command & General Staff College and Frunze Military Academy, Russia. The views expressed are his own.


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