X and Y: How Important are Sex Chromosomes in Gender Identity?

When we talk about sex and gender, there are a few things that need to be addressed. Biological sex is determined by the sex chromosomes that a person has; if someone has two X chromosomes (XX), they will be biologically female and will have female sex organs. If someone has one X chromosome and one Y chromosome (XY), they will be biologically male and have male sex organs. Gender is the external behaviour and characteristics which are typically expected of women and men; gender identity is an individual’s personal perception of having a particular gender. A person’s sex and gender identity do not always align, and this is called gender dysphoria or transgenderism. In this article, I will be exploring whether being transgender is genetic, as well as discussing the issues many transgender people face.

The argument I hear most often is that ‘you can call yourself what you want, but at the end of the day you’re still either biologically male or biologically female’. There are two faults that I find with this argument. Firstly, although seemingly supportive, this argument belittles the transgender experience because it shows that some people will never consider transgender individuals to be their identified gender, simply because they believe biological sex is fixed and that alone defines a person’s gender. Let me be clear: gender and biological sex ARE different. Secondly, biological sex is not as binary as some people think. There is a condition called Klinefelter’s syndrome in which an individual has the sex chromosomes XXY. So, is this person male because they have a Y chromosome, or are they female because they have two X chromosomes? Similarly, there is a condition called Turners syndrome in which an individual is missing a second sex chromosome, making them XO. Are these people male or female? What about true hermaphrodites who have both male and female sex organs? Are these individuals’ men or women? Or, the more important question, perhaps is: who has the right to tell another person what their pronouns are? So, if we can see that biological sex isn’t as rigid as we once thought, perhaps we can begin to see how gender is also fluid.

“But” I hear you say, “It’s not these peoples’ fault they don’t have typical sex chromosomes, it’s not their choice”, to that, I am about to show you that being transgender is also not a choice and is likely genetic too. Twin studies are often a good way to test whether genetics is playing a role; researchers compare how often specific traits occur in identical twins, who share 100% of their DNA, compared to non-identical twins, who only share 50% of their DNA (the same amount as in normal siblings). The aim is to see whether genetics or the environment have more of an influence on those traits. Whilst it is difficult to carry out twin studies on transgender individuals, not only because being transgender is very rare, but further finding transgender individuals who are twins is even less common, several studies have carried this out. One study has combined the results of these studies and found that if one identical twin was transgender, there was a 23% (biological female) and 33% (biological male) chance that the other twin would also be transgender. In comparison, there was less than 3% chance that both twins would be transgender in non-identical twins. This suggests that gender identity is influenced by a person’s genetics. So which genes are involved?

It is common knowledge that male and female brains function differently: female brains have significantly more activity than male brains, particularly in areas assigned to planning, judgment, impulse control and shifting attention. However, male brains show more activity in visual and coordination centres, and they also tend to produce more serotonin, which modulates mood. What is interesting, is that the brain activity and structure in a transgender person’s brain more closely resembles that of their identified gender, rather than their biological sex. Because of these findings, genetic studies to determine a cause of gender dysphoria have focused on genes involved in brain development and function.

In the brain, oestrogen receptor pathways during development are involved in establishing whether the brain will be more masculine or feminine. One study investigated the genes involved in this feminisation or masculation of brains in transgender people. They found that there were 21 changes in 19 of these genes. In biological males/transgender women, this gene change meant that oestrogen exposure either did not occur, or was altered, meaning the brain did not go through typical masculation. In biological females/transgender men, this gene change meant that oestrogen exposure occurred when it shouldn’t have, meaning the brain went through inappropriate masculation. Although this study is just one example of a set of genes which may cause gender dysphoria, it is important to note that there are many genes involved in gender identity are not necessarily all present on the sex chromosomes. This means that if there are changes to the genes involved in gender identity, this could lead to a disconnect between gender identity, regardless of what sex chromosomes are present. Scientists have not yet investigated all these different genes, but there is a high likelihood that mutations here may also cause gender dysphoria.

Whilst only 0.2% (biological female) and 1.4% (biological male) of the UK population experience gender dysphoria, they are at a significantly increased risk of experiencing discrimination, sexual violence, depression, and suicide: 41% of transgender individuals were victims of a hate crime in the last 12 months; 70% of transgender individuals have received death threats; nearly half of transgender individuals have attempted to commit suicide and are twice as likely to experience suicidal ideation. This may be due to the sheer amount of psychological distress transgender individuals experience, or due to the discrimination and prejudice they face daily. I prefer to think that these horrific statistics are due to the outdated views and lack of understanding of those who discriminate and hate against transgender individuals, because this, at least, can be addressed. I hope my children and my grandchildren will grow up in a world that is much more open-minded than the one we currently live in, but the only way to do this is to stop the intolerant, rigid attitude and open ourselves up to change and acceptance by educating ourselves on these types of issues. People need to understand that being transgender is not a choice. It is not a whim. It is not a cry for attention.

References

http://www.hawaii.edu/PCSS/biblio/articles/2010to2014/2013-transsexuality.html

https://www.bbc.co.uk/news/explainers-53154286

https://www.sciencedaily.com/releases/2018/05/180524112351.htm

https://www.amenclinics.com/blog/7-differences-between-male-and-female-brains/

https://centerforhealthjournalism.org/2019/10/30/transgender-youth-are-dying-suicide-rates-far-higher-their-peers

https://www.mind-diagnostics.org/blog/gender-dysphoria/gender-dysphoria-vs-transgender-whats-the-difference

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/721642/GEO-LGBT-factsheet.pdf

Disclaimer

The information in this blog is for information and entertainment purposes only. I am not a medical professional, so I have never and will never give medical advice in this blog. You should always speak to a healthcare professional about your unique health needs. My opinions are entirely my own and do not reflect the organisations or people I work for. I only discuss published literature in this blog which are referenced with links.

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