Who cares about the transgender brain?

by Eric Llaveria Caselles


Part 1: What is science saying about the trans brain?

Part 2: Feminist neuroscience is also science!

Part 3: What is at stake with the trans brain?


In November 2014, a paper with the title “White Matter Microstructure in Transsexuals and Controls Investigated by Diffusion Tensor Imagingby an austrian research team lead by Georg Kranz was published in The Journal of Neuroscience. This was met with enthusiasm in the public media around the globe, ready to re-launch the idea of the transgender or transsexual brain (from now on, just trans brain in here). The basic notion revolves around the question whether the brains of trans people differ systematically and significantly from the brains of cis people, on whether there is something that might allow to tell the brains of trans people apart from the brains of cis people. This is not a new issue. In 1995, following the publication in Nature of “A sex difference in the human brain and its relation to transsexuality, the New York Times published an article with the title “Study Links Brain to Transsexuality, and United Press International reported under the title “Difference found in transsexual brain. In both cases the authors report on the findings but include interviews with other scientists who comment critically and advance certain interpretations. In the UPI article, a psychology professor comments “the results show only a difference, not when or why the difference is developed. ‘People will say that since a part of the brain is different, it must be that transsexuals were born different. These results do not mean that. Period’”. In the last years, the tone has changed dramatically. In 2015, the austrian newspaper Die Presse issues at report with the title “Das Gehirn bestimmt das Geschlecht(The brain determines the sex). In Germany, Die Welt publishes “Transsexualität entsteht schon im Mutterleib(Transsexuality is developed in the womb). A conference in the Goethe University in Frankfurt under the title “Transsexuality: Exploring a Challenge for Society at the Intersection of Theology and Neuroscienceexplains “Thanks to the insights of neuroscience and bioscience research, transsexuality is now regarded as innate, with its biological basis in the brain”. In the spanish speaking countries, the news arrived somewhat earlier, following the publication of the research by a team around Antonio Guillamón, from the UNED. In 2012, the spanish newspaper ABC titled “La transexualidad está en el cerebro(Transexuality is in the brain), the mexican edition of the popular science magazine Quo asked “¿Existe el cerebro transexual?(Does the transexual brain exist?) and found the answer to be a clear yes, and in Argentina, La Nación titled a report from 2011 on this same research “Cuando el cerebro tiene un sexo diferente al del propio cuerpo(When the brain has a different sex that the one from your body). Early this year, in the Scientific American, Francine Russo gets more a bit more nuanced again “Overall the weight of these studies and others points strongly toward a biological basis for gender dysphoria. But given the variety of transgender people and the variation in the brains of men and women generally, it will be a long time, if ever, before a doctor can do a brain scan on a child and say, “Yes, this child is trans.””.

The trans brain is becoming a prominent idea when addressing trans people’s issues, whether proven or not. The accumulation of data apparently pointing towards one and the same conclusion could be a reason for why the idea is so often discussed, but having more people talking about something is not a proof of its existence – if anything it is a testimony to the attractivity or instrumental potential of an idea. In fact, the different reports vary a great deal in the degree of certainty awarded to the facts from totally proven to probable but not yet conclusive. There is definitely a lack of critical engagement with the scientific research and a tendency to rephrase the paper and adopt its conclusions. The idea of the trans brain extends to the question whether the difference is inborn or not, another reenactment of the nature-culture debate (sorry, I wish I could spare you this). Here again, the reports vary greatly depending on how nuanced and careful their understanding of  biology and brain development are. Some explicitly stay away from making conclusions while others claim as a fact that trans people are born trans.


Part 1: What is science saying about the trans brain?

I want to avoid the strategy of listing all of the evidence in favor and against the different claims and play them against each other. Instead I will try to make an more general argument about the methods, theories and practices in neuroscientific research on trans people. I will start by taking a look at what Georg Kranz and his team did and what evidence did they found. They selected 23 transmen and 21 transwomen (none of which had taken any hormones so far), 23 ciswoman and 22 cismen and scanned their brains using Diffusion Tensor Imaging. This technique captures differences in the structure of the tissues in your body. In this case, the researchers looked at the white matter of the brain. The white matter is made of the axons of neurons, and it´s white because it is covered in fatty tissue. They also collected further information about each of the participants (and here I am using their vocabulary): sex (male or female); gender identity (male, female); hormone levels (how much testosterone, estrogen and progesteron was in their blood); and sexual orientation (attracted to men, women or to both).

By looking directly at the scans, the researchers won´t be able to tell that many things. In order for the scans to give them the specific information of the brain tissue, they are modelled according to brain atlases and rendered through software to make them readable.  What they can see after the data has been processed is that there are differences in the tissue of the white matter between their group of cismen, ciswomen, transwomen and transmen. The specific difference they found is the degree of diffusivity, that means, the easiness which which water molecules move in the brain tissue. In this respect, ciswomen have the highest diffusivity value, followed in this order by transmen, transwomen and cismen.

In the next step, they try to find what is the cause of this differences: sex, gender, hormones or sexual orientation. After running statistical analysis, they state: “in our study, we find robust differences between investigated groups in MD, AD and RD (diffusivity values) indicating that biological sex and gender identity both contribute to observed group differences”. The conclusion is then that there are differences in the diffusivity of white matter tissue and that these differences are related to both sex (male or female) – and here specifically linked to testosterone – and gender identity (male or female). In case you are now wondering why there is no specific mention of trans brains is because of how the researchers conceptualize being trans. Basically, they see trans people as having an “inverted” relationship of male biological sex and female gender identity or the other way around. In their logic, this allows them to observe “gender identity” isolated from “sex” in the brain when they compare cismen with transwomen and ciswomen with transmen.

Having found these differences does not give any information about how they came to be, what effects they have in terms of functioning and how they specifically relate to sex and gender identity. Basically, it says nothing about what these differences in brain tissue mean. We now enter the realm of hypothesis and theories! The authors of the paper priviledge the effect of hormones to explain their findings, but they are very explicit about the blind spots of this theory: “Although brain structural sex dimorphism have been linked to hormonal differences between the sexes during fetal development, puberty, or adulthood, the specific biological mechanisms underlying these differences remain to be determined”. Towards the end of the paper, they remark how their interpretation is limited by their theoretical frame: “our interpretation of study results mainly focused on a potential hormonal influence in the womb and early neonatal life. So far, we did not touch on genetic determinants of gender (…)”. That means that they are aware of different theories or approaches. Conveniently, they don´t mention social factors, experiences etc, which is quite troubling. The interpretations and theories that the authors consider or mention (hormonal and genetic) become therefore biologistic in that they try to address complex phenomena, like gender identity, only by looking at physiological factors. However, as I will show later, not all Neuroscience works like that. So, when the authors state that “our results strengthen the notion of an observable and measurable biological basis of gender identity and put gender dysphoria into the realm of human physiological variation”, they are operating within a very specific theoretical frame: the organization/activation theory as formulated by Dick Swaab. This model acknowledges only male and female sex and male and female gender. Both are defined during pregnancy and in the early months after birth. From the perspective of the individual, genes and hormones will determine sex, gender identity and sexual orientation. Swaab has a two-step model of sex and gender in which sex stands for genital differentiation (male or female) and gender for brain differentiation (male or female). In a first step, between the 6th and 12th week of pregnancy, the genital sex of the baby will develop as either male or female. After the differentiation of sexual organs, the differentiation of the brain occurs. The brain anatomy and circuitry will be organized during pregnancy and the first three months after birth as either male or female mainly through the effects of sex hormones. In puberty, the brain circuits will be activated by sex hormones. In his own words: “Structural differences in the brain resulting from the interaction of genes, sex hormones, and developing brain cells are thought to be the basis of, e.g. sex differences in gender role (behaving as a man or a woman in society), gender identity (the conviction that one belongs to the male or female gender) and sexual orientation (heterosexuality, homosexuality or bisexuality). But even operating within this frame, the results are far from clear as authors themselves state: “The differences that we have seen are significant, but not definitive. By this I mean that the groups, at least in part, overlap with each other. You can not be said female, male or transgender just looking into his brain structure. It is disappointing then to see how they are purposefully misleading in their press release: In a current study, brain researcher Georg S. Kranz of the University Clinic for Psychiatry and Psychotherapy of the MedUni Vienna was able to demonstrate that the very personal gender identity of every human being is reflected and verifiable in the cross-links between brain regions”. Unless we now all agree of defining our gender identity in white matter diffusivity values instead of all the wonderful terms and expression, this is a really gross reductionism and an unjustified extrapolation of the empirical evidence to complex categories that are undeniably also historically and socially shaped.

Before going back to how neuroscientists think about sex and gender, I want to point at another crucial aspect that all the reports fail to mention and is a problem in most of neuroscience research: the selection of participants. Apart from it being too small to be in any way representative, the participants are selected according to a specific definition of  cismen, ciswomen and transmen and transwomen. If someone does not meet their definition, they will be rejected as participants. For example, cismales and cisfemales whose sex steroid levels are not within a certain range considered normal, will be rejected. Cis and trans people that show any “mental problems” (apart from being trans, you know… ) will also not be selected. This might be especially problematic if you want to talk about trans people because the prevalence of mental health problems in the trans community is much higher than average. Their sample only includes trans people who have reached to a clinic, meet the diagnostic criteria established by the DSM for and want to take hormones and have surgery. This is a very critical issue when you are doing research on trans people. Because in Austria (this is where the study was done), as in many countries, the state and the medico-legal institutions have the factual power to decide over trans people about our body and our healthcare as trans persons, we are not free to define ourselves. While a lot of trans people might find themselves within the range of what the DSM defines as trans, many others don´t and will either stay outside of the medico-legal institutions or go and say and do what they have to do in order to get access to healthcare. It is, again, a very narrow sample that they are looking at that excludes many trans people and people with other gender identities that differ as well from male and female.


Part 2: Feminist neuroscience is also science!

So back to gender and sex in brain research. Apart from one article, all of the media fail at presenting critiques of the model used by Kranz and his team, as well as alternative theories from Neuroscience. Only Sarah Hampson on The Globe and Mail in Canada in her article “Science in Transition: Understanding the biology behind gender identitypoints to the controversy surrounding Dick Swaabs model. However, she does it in a very frustrating way: “The idea that male, female and transgender brains are different upsets feminists, for example, who maintain gender is a social construct. (“Nonsense,” Swaab says to me, when I float this idea)”. So much for a balanced discussion. It is really troubling how science is constructed as a homogeneous space and how critical voices within Neuroscience, especially feminist researchers, are being systematically silenced. This misrepresents the fact that research is conflicted and debated. Showing that theories and models are object of discussion at least gives the readers the option to think by themselves or seek for further information. There happen to be critical and feminist neuroscientists doing research published in fancy journals too. Why not see what they have to say?

Feminist and critical neuroscientists are not saying that there are no differences between brains, or that gender is merely a social construct. They agree on the fact that neuroimaging methods show differences between brains, but they are developing a different model. This model is, like the model used by Kranz and his research team, a theoretical construct, and is as such equivalent in terms of scientific credibility. In the interpretation of these findings however, they put more weight on the idea of brain plasticity when explaining brain development (which, as a reminder, is explained in Swaab´s model from genes and hormones). The plasticity of the brain means that what activities you do in your life, what experiences you go through etc will influence the anatomy of your brain as it develops. This questions the assumption that because there is an observable difference in the form of the brain, the explanation has to be only biological. It means that to explain the differences in the brain between people with different reproductive organs, genitals, hormone levels, gender identities… you need to take into account the different experiences that people make in society as men, women, trans, genderqueer, intersex, etc. By this, critical and feminist neuroscientists are taking the brain out of a biologistic scheme and seeing it as shaped both by physiological factors and social factor. Anelis Kaiser writes in her 2012 paper “Re-Conceptualizing “Sex” and “Gender” in the Human Brain: “Today, bio-materiality is perceived as “in the doing” – we know that the brain can increase its neuronal response strength, can augment its synaptic density, and can expand its representation across cortical areas throughout life – all of which are subsumed in the concept of neuronal plasticity. Researchers from biosciences operating with the biological matter always knew that brains are not the result of inborn, hardwired, or unchanging biological processes, but instead are responsive to ongoing external and social experiences”. Following this thought, the members of the NeuroGenderigs Network prefer to write Sex/Gender instead of “sex” or “gender” when they refer to the human brain, because the biological and the social components can´t be disentangled.

Another key element of the critical neuroscience model of sex and gender in relation to the human brain is that it is not modelled after genital difference. In genitals, it can be argued that there are statistically two types of genitals that are most common in humans and that you can tell them apart by looking at them, even if they vary in many ways within their own types. According to the feminist model and against what the organization/activation model proposes, there are no two types of brains that match the types of genitals. In Sex beyond the genitalia: the human brain mosaic”, a team of neuroscientists analyzed the MRIs of 1400 human brains and found “extensive overlap between the distributions of females and males for all gray matter, white matter, and connections assessed” and that “most brains are comprised of unique ‘mosaics’ of features, some more common in females compared with males, some more common in males compared with females, and some common in both females and males”. This is in accordance to their definition of gender. While the organization/activation model defines gender within a binary of male/masculine or female/feminine and treats them as mutually exclusive, feminist neuroscientists acknowledges a much wider range of behaviours, identifications, expressions, etc that don´t fit in clear cut distinctions of masculinity and femininity. It also accounts for the fact that what counts as feminine or masculine change across time and space.

As I advanced, my point is not that I think feminist neuroscience has the right answers and I want you to believe me. My point is that if we are talking about the findings of some research, it is necessary to be aware of how scientific knowledge works and what its limits and weaknesses are. To be able to separate what the evidence is, how it is produced, what the theory and hypothesis are and on what assumptions are they based. It is necessary to take into consideration not only one line of research on the topic but present the alternative approaches and perspectives. It is important to acknowledge that some questions can have different answers and that some questions can’t be answered yet. And it is important to take a look at who is asking what question and why.


Part 3: What is at stake with the trans brain?

So, if there is no such thing as a trans brain for the moment, who is talking about it and for what purpose? First, we have some neuroscientists talking about trans brains. Following the idea of objectivity and being value-free etc, I will just assume that they are motivated by mere curiosity and interest in learning about how brains work, human biology etc. But as scientists who pursue a career, they are invested in certain theories and models on which their research is based and to which it supposedly adds. In the case discussed here, the stakes are really high on the idea of gender identity being a neurological or physiological trait. This would give neuroscientists even more attention, authority and potential funding. Trans people´s brains come in very handy for creating evidence that will support their claim of gender identity being an outcome of your brain physiology. This is dependent on accepting the hypothesis on which the organization/activation theory is based: that there are only two sexes and two gender identities (male and female), that both male and female are two exclusive categories defined by either genitals or a series of behaviours, etc. For scientists working on this model, trans people are used because they allow them to isolate “gender identity” by comparing them to cis people. For example when they compare the brains of transmen to ciswomen, the neuroscientist following this model will claim that any observed differences are the reason for the male gender identity of transmen.

Second, we have experts and authorities of all kinds talking about the trans brain. The crowd here is quite mixed, scientists, psychiatrists and psychologists, well-meaning trans allies and kind spirits trying to support trans people. What they have in common is the use of the idea of the trans brain to argue for the acceptance of trans people´s lives and the legitimacy of our access to healthcare. Georg Kranz is quoted saying “We show that trans sexuality is a human biological variation, and I think that is a kind of relief for transgender people,” (Yes, because before they told me, I was wondering whether I was a worthy human being..). It is the long known equation of physiological trace = biological trait = inborn & unchangeable quality = nature = acceptable. This equation in some form has historically harmed most of the world population apart from a few white western cismen (see: sexism, racism, ableism, homophobia…). Joshua Safer, one of the authors of a review article titled “Evidence Supporting the Biological Nature of Gender Identityis quoted stating: “This paper represents the first comprehensive review of the scientific evidence that gender identity is a biological phenomenon. (…) As such it provides one of the most convincing arguments to date for all medical providers to gain the transgender medicine skills necessary to provide good care for these individuals. I guess that so far it was ok for medical providers to be shit to trans people. In this video on the science of transgender, these well-intentioned reporters repeat the trope that being trans,”it´s not a choice. It´s who they are, and science can back that up”. They reproduce uncritically the theory of biologically determined gender identity and relate that to a social science study claiming that “76% of participants knew they were transgendered before they left elementary school” and a psychological study that found that “kids as young as five, who identify as trans, showed a consistency of gender identity across various measurements”. The worst part comes when the guy mentions how he saw Laverne Cox speaking (trans-ally points?) and “she said exactly the same”. Basically, Laverne Cox credibility when talking about her own experiences depends on whether they match or not what some scientist-expert is saying. Using the trans brains idea, or using any idea from science without a critical examination of what you are buying into, will feed into the dynamic of expert authority having credibility and the power of definition in society about who is trans, who is not, what trans people need, etc. This subtle mechanism is made transparent when idea of the trans brain is related to the hope of being able to diagnose trans people by looking into their brains. Riccardo Guidi asks in an article on the occasion of the launching of a Gender, Health and Rights seminar series at the Center for Gender Medicine at the Karolinska Institut: There are transsexual people who have always known about their identity, while others may have discovered it through years in life. Because of construction and constraints of society, there is confusion – sometimes even in our own understanding. Could this work help us to identify a person real gender identity with a quick brain scan?”.

Obviously, also trans people are talking about the idea of the trans brain, and some are quite happy about it. The thing is that the idea of trans being an inborn biological condition is instrumentally helpful to achieve certain improvements in the quality of life and in the well-being of many trans people. This is something that can’t be dismissed lightly and it is an argument to use it. Personally, I think it is a legitimate move because we don´t live in unicornland and we have to deal with medical institutions, health insurance companies, with the state, the police, job market, etc. However I think it is important to be aware that if your are using that argument, the trans brains don´t come alone. They carry a heavy baggage that perpetuates discriminatory and oppressive power dynamics (have to spell out the points a bit or formulate them more accurate):

  • it does not take into account the limits of scientific research and knowledge production
  • it does not take into account other models of sex/gender in the brain
  • It feeds into the authority and credibility of experts over trans people
  • it perpetuates a system in which the state and medical institutions decide for trans people
  • It feeds into a logic by which trans people should only be accepted because “nature”
  • It is based on a binary understanding of sex and gender that excludes genderqueer and non-binary people
  • It is based on a normative understanding of male or female gender identity, behavior or presentation
  • It is based on the idea that gender and sex are both biological phenomena
  • It feeds into the idea that gender differences are unchangeable and not shaped historically or by society
  • It has a very narrow definition of what being trans means
  • it reduces people to their brains
  • it feeds into seeing trans people as the problem instead of violence and discrimination against trans people.

In my opinion, if you are a cisperson trying to make the point that trans people should be respected and treated as human beings, don´t do this on the base that some scientists might have been able to proof or not some biological evidence. Do it on the base that trans people are human. If you are a scientist trying to figure out whether there is a trans brain, don´t pretend you are doing something that will benefit the trans community. Also, be more vocal and transparent about the limitations of your research. Take into consideration other approaches or argue why you have decided against them (or at least acknowledge that you have not taken them into consideration). And if you are someone that actually wants to support trans people, inform yourself, read texts by trans people, don´t speak for trans people, look for your local trans support organization and help with problems affecting the trans community. You will find that figuring out whether we have an inborn trans brain is not one of them.

If you are a trans person, do what you need to do. Take care.

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One Response to Who cares about the transgender brain?

  1. zoebrain says:

    “If you are a scientist trying to figure out whether there is a trans brain, don´t pretend you are doing something that will benefit the trans community. ”

    I don’t. Haters gotta hate, regardless. Moreover, if you go into a research study trying to prove something for a social good, you’ll end up coercing the data into telling you what you want to hear, not what it says.

    If I have a social concern, it’s regarding Intersex, rather than Trans, people. Easier to study, fewer variables to shackle.

    “It is based on a binary understanding of sex and gender that excludes genderqueer and non-binary people”

    Not after you’ve studied it for even a short time, no. Many papers have been written assuming a strict binary model, not as a reality, but as a useful tool, a crude approximation known to be wrong, but still aiding discourse. All models are wrong. Some models are useful.

    A bit like the “spherical cow”, or the simplifications used in most engineering work. When calculating the trajectory of a cue ball in pool, Newtonian mechanics with perfectly elastic collisions works well enough for most purposes, even though we know both are wrong.

    “it is based on the idea that gender and sex are both biological phenomena”

    No, that’s an (inevitable) conclusion, not an initial premise. It’s also obvious that both sex and gender are at least partly socially constructed. The observable facts don’t change, the interpretation of them does, between different places and different times.

    This article is more right than wrong, though I would have preferred to see a bit more on the limits to neuroplasticity. There are fairly strict bounds on it. The points about the uncertainties involved in neuroimaging are excellent though. Just remember to apply the same standards elsewhere.

    My concern is to get the science right. If that aids Trans people, good. If it harms them, then we need to do additional non-scientific activist work to ameliorate the harm. But ignoring reality never works in the long term, we must work with it.


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