The Gay Gene and the Ethics of Genetic Testing

gay gene

Over 20 years ago, Dean Hamer – an American geneticist – and his colleagues published an investigation into the possible genetic basis of sexual orientation. The paper, which analysed genetic data from 114 families containing homosexual men, reported an association between genetic markers on the q arm of the X chromosome (chromosomal region Xq28) and male homosexuality: and so ‘The Gay Gene’ was born.


On the surface, the concept of a gene that determines homosexuality may seem counter-intuitive: according to Darwin’s theory of evolution, genes that equip an organism with an advantage are more likely to be passed on to the next generation. This is because by having the advantage that organism is more likely to survive, and is therefore more likely to have more opportunity to mate and pass on its genes (including the gene which is giving them an advantage). If were a strong genetic factor determining male homosexuality, it seems counter-intuitive that this gene would be passed on, as it would be unlikely to confer an advantage with regard to the likelihood of yielding offspring. (Notably, there are some theories as to how genetic determinates of sexual orientation may have arisen – but these will not be discussed here).

Hamer and his colleagues’ findings have never been replicated, and their work has been the subject of both critique and intrigue. Yet The Gay Gene has lived on through popular science writing, newspapers, the web and undoubtedly whatever new media platforms the future brings, giving this (somewhat scientifically ill-founded) gene a life of its own.

Leaving the controversial ‘genetics of homosexuality’ aside, The Gay Gene’s presence (hypothetical or otherwise) provokes a number of questions, least of all regarding the consequences of a confirmed discovery of a gene that either predisposes or universally determines sexual orientation would be.

I’d like to take a few moments to ask some questions relating to genetic testing as a whole, and pose a few thoughts where I feel comfortable doing so. These questions will start by using genetic diseases as extreme examples of traits that may be useful to test for, and will then move on to thinking about non-disease traits. There are many strongly opposing views on the area, and so these comments are reflective of schools of thought within the scientific community – not necessarily those of any one person in particular.


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Is it right to test individuals for genetic diseases?

This is largely accepted as being ethical (providing, of course, that there is consent for testing). This can inform patients of risks of future disease, and may even allow early treatment interventions or application of preventative medicines. It can also aid diagnosis of genetic conditions, and may allow doctors to distinguish one disease from another, allowing more effective therapies to be given.
All sounding good so far?

Is it right for parents to test their child for a genetic disease?

Children cannot legally give informed consent, as they are not viewed as being able to understand the magnitude and complexity of genetics and genetic diseases, and so this right would usually fall to the parents. But is it ethical to allow an individual to be tested for a genetic disease when they cannot be acknowledged to understand the implications of the testing? This is an issue that not only plagues genetic testing but the medical profession as a whole- at what age is a child deemed fit to decide his or her treatment?

Is it right to test to test an unborn child for a genetic disease?

This may well allow parents to prepare themselves for the challenges of raising a child with disorders such as cystic fibrosis or Down’s syndrome, and may give them valuable time to benefit from advice and counselling on how to care for such a child. This leads us on nicely to the next question…

Do parents have the right to terminate a pregnancy based on a genetic test informing them that the child will have a debilitating genetic disease?

Considering cystic fibrosis as a one such genetic disorder:
A very grey area with strong arguments on each side. In terms of saving money on treatment and avoiding the challenges of bringing up a child with CF, it might be seen as beneficial to terminate – but do even the parents have the right to make that decision? If so, is there a time period after which such a decision could not be made? At what point it the developing human a person rather than a ball of cells?
In a world of better treatments and evolving medical approaches for tackling genetic disorders like CF, where do our ethical boundaries lie? Do these boundaries change depending on whether the disease is treatable or not?

Is it right to test embryos for genetic disorders during IVF and choose to implant only those without these detrimental genes?

Again, arguably this could be beneficial, and may be the only way that parents who know they are carriers of certain genetic disorders may be comfortable having children. On the other hand, do we have the right to pick and choose our favourite embryos?

Do parents have the right to test an unborn child for genes that only increases risk of disease, or gives rise to disorders that are easily treatable?

Is it ethical to terminate based on only an increased likelihood of disease? Should they be allowed to terminate the pregnancy if there’s a 90% chance of developing a severely debilitating disorder? What about 75%? … 50%? … 25% … 5%? Who gets to decide what is an ‘acceptable risk’? Could this level of risk be off-set by the disease being easily treatable?

If a couple REALLY wanted a girl rather than a boy, should they be allowed to ‘screen’ embryos and only implant female ones during IVF?

In an age of potential “designer-babies”, where parents could be picking their children’s eye colour and hair colour, choosing certain characteristics by screening embryos certainly isn’t beyond our capabilities. But is it right? This question has seen a lot of debate since the inception of genetic testing and we won’t see an answer to it any time soon.

What if a different couple REALLY didn’t want a homosexual child – would they be allowed to screen embryos for The Gay Gene?

Do parents have the right to test an unborn child for the “gay gene”?

If parents have the ‘right’ to information about genetic disorders their unborn child may or may not have, do they also have the right to information about their characteristics and personality – hair colour, eye colour… sexual preference?

Could the results of a test for the gay gene be grounds for terminating a pregnancy?

Now we’re starting to see how genetic testing can become truly controversial. If parents are homophobic, should they be allowed to test their child for the gay gene? Should they be allowed to terminate a child based on that test?

Could the law obligate a mother to carry an unwanted pregnancy for 9 months?

If it is illegal to terminate – should a mother be forced to carry an unwanted child until it is born? Can the law really obligate parents to do this? If not, we’re condemning termination based on the identification of the child’s sexuality. Unstoppable force meets immovable object.

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As it currently stands, we cannot genetically test for sexual orientation – whether on a pre-implanted embryos, during pregnancy, or after a child has been born – but imagining that we could has raised some pretty hefty questions.

What could happen if we do find a gene for sexual orientation? Could countries in which homosexual practice is illegal use these kinds of tests to actively identify and persecute individuals?

Could we find genes for other characteristics like political affiliation? What could we do if we identified genes for racism? What about a gene for making people selfish? Where do we draw the line on what is right or wrong to test for, and who has the right to this information?


Lots to think about.




Note from the author:

Although both perplexing and intriguing, I personally am strongly opposed to further investigation into finding a genetic basis for sexual orientation. Whilst my own scientific interest lies in research that has a direct application to human health and disease, I am a supporter of “science for science’s sake” (I believe we should learn more about the world purely because it is interesting to do so). However, this line of research (in my opinion) simply opens up too many possibilities for misuse of knowledge – not only for the reasons described above, but because of the existence of authorities and persons (present and future) who believe that homosexuality is wrong. The potential to misuse and abuse knowledge of such a gene to ‘diagnose’ people with homosexuality is too great, and the potential consequences too costly.



Hamer DH, Hu S, Magnuson VL, Hu N, & Pattatucci AM (1993). A linkage between DNA markers on the X chromosome and male sexual orientation. Science (New York, N.Y.), 261 (5119), 321-7 PMID: 8332896
Baron M (1993). Genetic linkage and male homosexual orientation. BMJ (Clinical research ed.), 307 (6900), 337-8 PMID: 8374408
O’Riordan K (2012). The life of the gay gene: from hypothetical genetic marker to social reality. Journal of sex research, 49 (4), 362-8 PMID: 22720828

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You may also enjoy: “Porn and Working Memory” from this author.

5 responses to “The Gay Gene and the Ethics of Genetic Testing

  1. I think the issue here is that being gay is not a disease, so the question “is it right to test for a disease” is a completely different matter than “is it right to test for a gay gene, whether it exists or not.” I’m not at all surprised that they could never reproduce those results: there are so many identical pairs out there where only one of the two is gay, isn’t that enough evidence to undermine any genetic basis ?

    • We totally agree that being gay is not a disease, and we don’t want to infer that at all. The reason we’ve put the two topics into one post is that they raise similar issues about genetic testing as a whole which we think is a really important topic that needs to be discussed.

      That’s a really interesting point you made about twin studies actually, and not something I had thought about.

  2. Hi there,

    Thanks for commenting. You are of course correct – being gay is in no way a disease. The purpose of this article is to highlight the ethical implications of our growing ability to find genetic causes of common traits.
    With regard to your comment on identical twins – you’re right that there are a lot of twins out there with “disconcordant” sexual orientation (ie. their sexual orientation differs). However, this is also true of many diseases that are known to have some genetic basis.
    It is much easier to think of diseases with strong genetic associations – like CF mentioned about – but the vast majority of genetic disease is from not from a single gene defect. These diseases arise from multiple genes which convey discrete increases or decreases in overall risk of acquiring a trait (the trait being disease in the case of genetic diseases). Because of the nature of these diseases and interactions of both known and unknown environmental factors, simply looking at frequencies in monozygotic (identical) twins can under-represent genetic susceptibility/chance of acquiring traits, and can lead us to ‘miss’ genetic factors of traits.
    I do not personally believe that there is a strong (single) genetic variant for determining sexual orientation, but imagining that there were has allowed us to explore some very important ethical issues in this piece.
    I do hope you enjoyed reading it 🙂

    (author of this post)

    • We totally agree that being a woman is not a disease. The whole point of the article is in trying to link genetic disease (so debilitating diseases that would cause a person to need help in looking after themselves for their whole life) to “designer babies” where parents choose physical attributes (eye colour, gender, sexual orientation) to get a conversation started on the ethics of looking for these things in an unborn child.

      Thanks for taking the time to comment 🙂 We hope you enjoyed reading it.

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