Antonio Guillamón, 78, relates that, when he redirected his scientific work from the study of the sexual differentiation of the mammalian brain to gender identity, his interest “was not aimed at transgender people.” “I wanted to compare trans people [those who perceive an inconsistency between their physical features and the gender they feel they belong to] and cisgender people [those in whom the physical features match the perceived identity] to understand the matter of identity, because it would be a bit dim to say: ‘Let’s see what is going on with the transgender people’ when we don’t know what is going on with the cisgender people either,” explains this professor emeritus from the National University of Distance Education (UNED) in Madrid, Spain.
Guillamón recently published the results of years of research in the book Identidad de Género. Una aproximación psicobiológica (Gender Identity. A psychobiological approach). There, among other data, he includes an estimate of trans people within the population: about 4.6 per 100,000 inhabitants, according to European data. Despite the fact that they are few, their reality causes opposing positions and even political debates. The scientist is aware of the uniqueness of his subject of study, even if he approached it with the same disposition that he has applied to other scientific matters during his career.
Both in his book and during the conversation, he shows that he does not want to settle the debate and has a genuine interest in understanding. “Science is not dogmatic. I propose a theory and then someone else can prove that it is not true, and I will stop defending it,” he says. However, he adds, “dogmatism abounds in politics and in social groups.” Regarding society in general and the acceptance of trans people, Guillamón believes that “we are in the process of humanization, and part of the humanization process is the acceptance of difference.” “What radically makes us fully human is accepting variation, variability and difference, all with the same dignity. That is the ethical path that still lies ahead,” he concludes.
Question. What are the main findings presented in the book?
Answer. We observed that there is a differentiation in the brain that prepares us to accommodate an image that takes from what society offers. Gender identity is a continuum in which extremes predominate. There are two large models, male or female, and a person adjusts to one or the other. In very few cases, there is an inconsistency between the biological sex and the model, but in the cases in which it occurs, we have observed that there are brain differences in cis and trans men and cis and trans women.
Prenatal genes and hormones prepare the brain for the development of the different gender identities, and boys and girls have stereotyped behaviors from a young age. In addition to the exposure to testosterone during puberty, boys have a higher exposure to this hormone during gestation, as well as a kind of mini-puberty in which there is another peak of testosterone during the first three months after birth. All these differences condition the gender identity in which a person will fit. Gender identity is not something that you choose. If you’re lucky, you can choose what to eat, but you can’t choose whether you’re hungry or not. Something as central to us as identity is not something you choose. This is also proven by the failure of conversion therapies.
Q. But there are people, like Israeli researcher Daphna Joel, who deny the existence of a male or female brain.
A. Joel says that there are overlapping traits, that the brain is a mosaic. But a brain will be more masculine or more feminine. There are no qualitative differences between men and women, except for one that is very important: the existence of the Y chromosome, and the existence of a gene on that chromosome, SRY, which differentiates the testicles and everything they produce. There is only one qualitative difference, but it exists, and that SRY gene is also expressed in the brain.
Even if, as Joel says, it is something of a mosaic, in the end there are three quantitative possibilities in the structures of the brain. Male over female, female over male, or no difference. It is the profile of all these measurements what ultimately makes someone feel like a man or a woman. We recently published differences in brain connectivity. How information is spread in a thousand brain nodes and how this communication varies in short periods of time. We have found four different groups of connectivity: cis and trans men and cis and trans women. The same four groups that we described at a structural level and were confirmed by a recent analytical study.
Q. There are remarkable data presented in the book, such as the difference between trans men in Europe, who are 2.6 per 100,000, and trans women, who are 6.8 per 100,000.
A. We have seen these variations in different countries at different times. The truth is that we don’t know what is happening right now. Speculating, on one hand there are social changes, because after all identity is determined by a biological matter, but we also adapt to the models that society offers us, and there is more flexibility today. But, also, I believe that industrial activity has altered our environment in this sense too. We have many polluting substances that affect the estrogen receptors, the androgen receptors, the metabolism of sex steroids.
Gender identity, for most people, is formed during the first two or three years of life; but this adaptation doesn’t have to be linear. There are people who reach puberty and still are not very well defined. As Dutch researchers have seen, a significant proportion of boys who reach puberty saying they are girls, or vice versa, later desists. Afterwards, they become aware of being homosexual people, content with their identity. Some reach puberty without having previously consolidated their identity, and sometimes identity is confused with sexual orientation.
Q. In Spain, are there many people who receive a gender-affirming treatment and then back down?
A. So far, thanks to the Gender Identity Units of public hospitals, not many have desisted. When someone arrives at the unit with anxiety and depression, a specialized psychiatrist analyzes if it is a reaction to a situation of distress, seeing that they feel like a woman and have the physique of a man or vice versa, or if it is a bipolar depression or a schizophrenia that should have to be treated first. If it is a reactive case, it goes directly to treatment. But if you suppress that evaluation process, the possibility of making a mistake is higher. Now, with the new law in Spain, it is going to be the family doctor, or an unspecialized endocrinologist who treats diabetes or cholesterol, the one who practically makes these decisions on demand. I think that the idea of depathologizing prevails over health. We can predict that there will be more transgender people desisting in the coming years.
As for the matter of depathologization, what happens is that transgender people seem to be immune to all the mental pathologies that cisgender people have. But not everything is minority stress. The problem is that now a person says: “I want this,” and they have to give it to them, but they don’t help them to see if it is something primary or reactive.
Q. When should gender-affirming treatments be started?
A. If you knew for certain that a boy that is 10 to 12 years old would be stable in his desire to be a girl for the rest of his life (or vice versa) what’s best is that the hormonal treatment starts with puberty blockers; then everything would work out perfectly. But there is no certainty in that, and the child has rights. The medical and ethical decision to give a blocker falls on parents and doctors. There are movements against blocking, because as much as you may explain to an 11-year-old kid that the blocker will have important effects on their body – effects that, in any case, are not known – it is difficult for them to understand. Currently, I only see one solution: specialists with clinical experience in the matter.
Q. Are gender-affirming treatments safe?
A. After puberty, hormonal treatment with testosterone (transgender boys) or estradiol (transgender girls) is not harmless; like any treatment, it can have adverse effects. In the brain, for example, we see enlarged ventricles. The first study on the effects of hormonal treatments on the brain dates from 2006. We did a second, broader study in 2014, which we published in the Journal of Sexual Medicine, and we offered an explanatory hypothesis. In the case of androgenization for a trans man, what happens is the same thing that occurs with the muscles when one takes an anabolic, the same anabolic and anti-catabolizing effects of the androgens in the rest of the body happen in the brain. In feminization, what we observe is that, as the thickness of the cerebral cortex and subcortical nuclei decrease, the ventricles expand. We recently showed that this happens because estradiol affects water metabolism in the cerebral cortex, not because the neurons shrink. We study the effects of the treatment in order to improve care for transgender people. We have proposed that a brain scan be included in the protocols every two years.
But absolutely nothing is known about the treatment of children with blockers on the brain. We have just been granted a ministry project to study them.
Q. How is this possible? Pharmacological treatments require knowing what will happen in the long term.
A. There is a magic phrase that states that the treatment is reasonably safe. It was said by Dr. Louis Gooren, a very experienced Dutch endocrinologist. You see transgender people in good health, but there are no long-term studies to know how they age or what effect some changes we have observed have in the brain. There is an article in which a treatment of this type is linked to meningiomas, but there hasn’t been a general trial of what the treatment is like. In children from the age of 11 or 12, puberty blockers are administered in order to suppress gender dysphoria, when this is considered necessary. Blockers are administered, but for a limited time.
Q. Does the change in legislation affect how treatments are approached?
A. In Spain the legislation has been changed, and the regional governments have modified the care procedures for transgender people. To my knowledge, in none of them, regardless of whether they were right or left wing, have the Gender Units that these governments created been consulted. In Spain, there are units that are international leaders on the matter. There’s the one in Malaga, which was the first, headed by Dr. Isabel Esteva, an endocrinologist who introduced the treatments. Others were later created at the beginning of the century: the Hospital Clínic, in Barcelona; Madrid’s Ramón y Cajal Hospital; also in Seville, in Bilbao, in Zaragoza, in Valencia, and elsewhere. These units have supported depathologization. But these specialists (endocrinologists, psychologists, psychiatrists) have not been asked anything at all and, as of 2019, they had already treated 9,000 people.
Q. Are the politicians not interested in listening to the scientists?
A. The world of politics moves with the preconceived idea that everything is social and that when it comes to gender identity, it is the person’s choice. The idea that one chooses as a volitional act is still rooted in the minds of the ruling class and the intellectual influencers. But there is an interaction between the social and the biological, and there is something as important as the self, which is a gendered self. There is a lack of understanding of gender identity, both from a biological and a social point of view. One clings to genes and genitalia and the other to the environment as shapers of identity. However, identity is the consequence of a very complex process involving genes, gonads, hormones, the brain, and the pre- and postnatal environment. It cannot be explained from the fringes, but from an overall view. It has to be seen as a process. That is what our group’s research leads to, and what I discuss in the book.
Q. There is the idea that we are a clean slate on which anything can be written...
A. I would ask them to prove that such a brain clean slate exists. That is not possible when you have three phases of testosterone action from the second trimester of pregnancy to puberty. That influences not only the brain but the entire genome, and it creates an epigenome, determining which genes are going to be expressed and which are going to be inhibited. In a collaborative study between the universities of A Coruña, Ghent and the UNED, we have shown differences in DNA methylation between cis and transgender populations in a series of genes, some of them related to development. We are not a blank slate at birth. Not only is it not blank; we would not even exist as the species that we are if we were a blank slate at birth. Darwin wouldn’t make sense. The social environment affects, first of all, facilitating models in which we are going to fit, but we are not starting from scratch. Children at birth do not start from scratch.
Q. Why is it so painful to experience that contradiction between what one feels and what one sees in the mirror?
A. It’s more than a feeling. It is the cognitive-emotional awareness of being a man or a woman. It is the self. The self is a gendered self. It is not an abstract identity. Up to now, we have always been told about an abstract self. But that self has been formed with the perception of one’s own body and in relation in time and space with other bodies and with the masculine and feminine form of the body. The contradiction comes from a rejection of the genitalia in transgender women and of the breasts in transgender men. This produces suffering. Family and social rejection, the stigma that leads to minority stress, aggravates this suffering.
Q. Why can’t they get used to seeing themselves in those bodies?
A. The construction of the self is formed by the perception of one’s own body; we need a cerebral self-representation of the body, also in relation to other bodies and what they do. What I think, which I have proposed in our publications, is that there are differences in the differentiation of the cerebral cortex that make the genitalia appear incongruous in transgender people. And this is not a pathology, but it causes suffering if it is not understood by everyone.