Transsexualism

Abstract

Transsexualism is the historical clinical term for a persistent, marked incongruence between a person's experienced gender and the sex assigned at birth, accompanied by a wish to live as the other gender and often to alter the body through hormones or surgery. The endocrinologist Harry Benjamin brought the term into medicine in the mid-twentieth century, and it survives as a Medical Subject Heading, but clinical practice has moved on: the DSM now speaks of gender dysphoria and the ICD of gender incongruence, shifting the diagnostic focus from identity to distress and, in the ICD-11, out of the mental-disorders chapter. This article treats transsexualism as a topic in the psychology of gender identity, tracing the evolution of the nomenclature, reviewing the prenatal differentiation hypothesis, setting out an epidemiology that depends heavily on how cases are counted, and describing gender-affirming care.

Keywords: gender identity, gender dysphoria, gender incongruence, sexual differentiation, transgender

Few areas of clinical psychology have seen their vocabulary revised as thoroughly as this one, and the revision is itself part of the subject. The word transsexualism names a diagnostic category built in the 1960s around the wish for bodily change, and the concept it encodes has been progressively reframed as the field's understanding of gender identity matured. The psychoanalyst Robert Stoller had by then drawn the distinction on which the whole area rests, separating biological sex from gender identity, the private sense of oneself as male, female, or otherwise (Stoller, 1964). Benjamin gave the clinical picture its first systematic description and its name, arguing that where the body cannot be brought into line with a fixed sense of self through psychotherapy, the humane course is to help align the body with the identity (Benjamin, 1966). The modern literature retains that clinical concern while discarding the assumption that the incongruence is itself a disorder, and the current diagnostic systems locate the treatable problem in the distress that may accompany it rather than in the identity (Reed et al., 2016).

What Transsexualism Is

Transsexualism, in its historical clinical sense, denotes a strong and durable identification with a gender other than the one assigned at birth, coupled with discomfort about the natal sex characteristics and, characteristically, a wish to acquire the bodily features of the experienced gender through hormones or surgery. The definition turns on the distinction that Stoller made central to the field: sex refers to the biological attributes of male and female, whereas gender identity refers to a person's own internal sense of being male, female, both, or neither, a sense that is established early and is highly resistant to change (Stoller, 1964). Transsexualism, on this reading, is not a disorder of biological sex but a stable mismatch between that sex and the identity, one that the older literature treated as a condition to be diagnosed and the newer literature treats as a variation of human gender experience that may or may not give rise to a clinical problem (Cohen-Kettenis & Gooren, 1999).

The term sits within a broader and now more common vocabulary. Transgender is an umbrella term for the many people whose gender identity differs from their assigned sex, of whom those who seek full medical transition, the group the older term transsexual picked out, are one part; its complement is cisgender, describing a person whose gender identity matches the sex assigned at birth. Because the descriptor transsexualism was defined around the desire for bodily change, it is narrower than transgender and carries the clinical framing of the era that produced it; this article uses it in the sense fixed by the Medical Subject Headings while noting throughout that clinical practice has moved on. Whatever the label, the phenomenon of a persistent cross-gender identity is well documented across cultures and history, and the scientific questions it raises, about how gender identity forms, why it sometimes diverges from natal sex, and how best to relieve the distress that divergence can cause, are the substance of the field.

The Evolution of Clinical Nomenclature

The clinical concept was assembled in stages, and its naming records a shift from pathologizing an identity to addressing a person's distress. Benjamin's The Transsexual Phenomenon gave the condition its first full clinical description, distinguished it from transvestism and homosexuality, and made the then-radical argument that when a cross-gender identity is fixed, medical transition rather than attempted conversion is the appropriate response (Benjamin, 1966). Transsexualism duly entered the third edition of the DSM in 1980 as a formal diagnosis. The fourth edition, in 1994, broadened the category and softened the language, but retained the framing of the identity itself as the disorder.

The decisive break came in the two current systems. The DSM-5, published in 2013, renamed the condition gender dysphoria, relocating the diagnostic criterion from the cross-gender identity to the clinically significant distress that may accompany the incongruence, so that a person comfortable in their identity is, by design, not diagnosable. The ICD-11, adopted in 2019, went further: it introduced gender incongruence and moved it out of the chapter of mental and behavioural disorders into a new chapter on conditions related to sexual health, a change intended to preserve access to care while ending the classification of a gender identity as a mental illness (Reed et al., 2016). The retention of Transsexualism as a MeSH descriptor is therefore a matter of bibliographic continuity, keeping the older literature findable, rather than an endorsement of the older frame; the term used to index a paper is not a claim about how the condition is best understood.

Biological Correlates and Etiology

No single cause of a cross-gender identity has been established, and the evidence points to a developmental process with biological, psychological, and social contributions rather than to one determinant. The most studied biological hypothesis is that gender identity is shaped during prenatal development by the same class of processes that sexually differentiate the body, but on a partly independent timetable. In this account, the genitals differentiate in the first months of gestation while the brain differentiates later, so that the two can in principle be exposed to different hormonal environments, opening the possibility that a brain may develop along a path that does not match the differentiated genitalia (Cohen-Kettenis & Gooren, 1999).

The hypothesis received its most cited support from a postmortem study reporting that the central subdivision of the bed nucleus of the stria terminalis, a small sexually dimorphic region of the hypothalamus, was in transsexual women closer in size and neuron number to that of typical women than of typical men (Zhou et al., 1995). Subsequent neuroimaging has extended the search to living brains, and a comprehensive review of the structural imaging literature concluded that the brains of people with gender dysphoria show a mixture of features, some resembling the experienced gender and some the natal sex, so that the evidence is best read as showing a distinctive phenotype rather than a simple reversal of sex-typical anatomy (Guillamon et al., 2016). These findings are correlational, drawn from small and heterogeneous samples, and cannot by themselves establish cause; their value is in showing that a cross-gender identity has measurable neural correlates rather than in proving any particular mechanism.

The figure sets out the two-stage timing that the prenatal hypothesis turns on: an early window in which the genitalia differentiate and a later, partly separate window in which sexually dimorphic brain structures do.

Figure 1

The Two-Stage Timing of the Prenatal Differentiation Hypothesis

Classification and Prevalence

Attempts to classify presentations within the category have a long and contested history. The most influential typology, proposed by Blanchard, distinguished subgroups of natal-male cases by their sexual orientation and associated features, arguing that these tracked meaningfully different clinical pictures (Blanchard, 1989). The typology has been widely used in research and equally widely criticized on both empirical and conceptual grounds, and it is presented here as a landmark in the classification literature rather than as a settled account; the current diagnostic systems classify by the presence of incongruence and distress rather than by such subtypes.

Prevalence is genuinely difficult to estimate, and the difficulty is instructive. A systematic review and meta-analysis of prevalence studies found that estimates drawn from the numbers attending specialist gender clinics were low, on the order of a few per hundred thousand, and noted wide variation across studies and rising numbers over time (Arcelus et al., 2015). Estimates drawn instead from population surveys that ask people directly about their gender identity are far higher, often by one to two orders of magnitude, because they capture people who never present to a clinic (Zucker, 2017). The gap is not a contradiction but a measurement lesson: a clinic-based figure counts treatment-seeking under a particular diagnostic threshold, while a self-report figure counts identity, and the two questions have different answers. Any single prevalence number is therefore uninterpretable without knowing how it was ascertained, a point the third demonstration makes concrete.

Assessment and Gender-Affirming Care

The framework for assessment and treatment is set out in the Standards of Care of the World Professional Association for Transgender Health, whose eighth version synthesizes the evidence into clinical guidance spanning assessment, hormonal and surgical treatment, mental health, and the care of adolescents (Coleman et al., 2022). The clinical model has shifted decisively from a gatekeeping posture toward an affirming one, in which the aim is to relieve distress and support a person in living in their experienced gender rather than to test the authenticity of the identity. Assessment establishes the persistence of the incongruence and the presence of distress, screens for co-occurring conditions, and ensures informed consent; the older insistence on a fixed sequence of hurdles has given way to individualized care (Cohen-Kettenis & Gooren, 1999).

Medical treatment, where indicated, uses gender-affirming hormones to induce the secondary sex characteristics of the experienced gender and, for some, surgery; the endocrine management of these regimens is now a developed subspecialty with its own evidence base and monitoring protocols (T'Sjoen et al., 2019). For adolescents, the Amsterdam clinic pioneered the use of gonadotropin-releasing hormone analogues to suppress puberty, a reversible intervention that pauses the development of unwanted secondary sex characteristics and gives time for assessment before any irreversible step, an approach now incorporated into the Standards of Care (Coleman et al., 2022). Access to such care has been associated with better mental-health outcomes; a study of transgender adults found that those who had wanted and received pubertal suppression in adolescence had lower odds of lifetime suicidal ideation than those who had wanted it but not received it (Turban et al., 2020). Long-term follow-up nonetheless shows that transition does not eliminate all risk: a Swedish register cohort found that people who had undergone sex reassignment had higher mortality and psychiatric morbidity than the general population, which the authors interpreted not as evidence against treatment but as showing the need for continued support after it (Dhejne et al., 2011).

Worked Example

Consider why a clinic-based and a survey-based prevalence estimate for the same population can differ so sharply, using the kind of figures the literature reports. Suppose a region of ten million adults. A specialist gender clinic serving it has, over its history, assessed and diagnosed people at a rate that works out to about 5 per 100,000, the low end typical of clinic-based counts (Arcelus et al., 2015). That yields an estimate of 10,000,000 × 5 / 100,000 = 500 people. Now suppose an anonymous population survey of the same region asks directly about gender identity and finds that about 0.5 percent of adults, or 500 per 100,000, report a transgender or non-binary identity, a figure in the range self-report studies produce (Zucker, 2017). That yields 10,000,000 × 500 / 100,000 = 50,000 people.

The two methods differ by a factor of a hundred, and the point of the arithmetic is that neither number is wrong. The clinic figure answers the question “how many people have been diagnosed and treated here?” under a specific diagnostic threshold and a specific willingness to seek care; the survey figure answers “how many people identify this way?” regardless of whether they ever approach a clinic. The historical descriptor transsexualism, defined by the pursuit of medical transition, corresponds to something close to the smaller, clinic-ascertained number, whereas the broader identity term transgender corresponds to the larger one. Reading a prevalence figure therefore requires reading the definition and the method that produced it; a single rate detached from its ascertainment is, as the demonstration shows, uninterpretable (Arcelus et al., 2015).

Discussion

The history of this topic is a history of the field learning to separate three things that the original concept fused: the biological sex of the body, the identity of the person, and the distress that a mismatch between them can cause. Benjamin and his contemporaries treated the wish for bodily change as the defining feature and the identity as the thing to be diagnosed; the modern systems treat the identity as a variation to be respected and the distress as the thing to be treated, which is why the DSM moved to gender dysphoria and the ICD moved gender incongruence out of the mental-disorders chapter altogether (Reed et al., 2016). This is not merely a change of words. It changes who is counted as having a condition, what the goal of care is, and where the burden of justification lies, and it is the reason the retained MeSH term must be read as an index label rather than a clinical position.

The scientific questions remain open in a way the clinical framework does not resolve. The prenatal differentiation hypothesis is supported by suggestive neural findings but not established, and the samples remain small and heterogeneous (Guillamon et al., 2016). The epidemiology is dominated by the ascertainment problem, so that the sharp rise in clinic referrals over recent decades is genuinely ambiguous between a real increase, greater openness, and better access to care (Arcelus et al., 2015; Zucker, 2017). And the outcome literature, while increasingly favourable to affirming care, still shows elevated long-term risk that argues for sustained support rather than treatment as a one-time event (Dhejne et al., 2011; Dhejne et al., 2016). The field's progress has been less in settling the causal question than in building a clinical and ethical framework that does not depend on settling it.

Cognitive Implications

Transsexualism earns its place in a cognitive-psychology reference through the construct at its centre: gender identity is a component of the self-concept, the organized cognitive representation a person holds of who they are, and its persistence and resistance to change are properties of that representation rather than of the body it may or may not match (Stoller, 1964). The clinical picture is in part a discrepancy between two internal models, the represented gender and the perceived body, and the distress that can follow is the affective signature of a mismatch the mind cannot easily revise, which is why the current diagnostic framing locates the disorder in the distress rather than in either model alone (Reed et al., 2016). Body image, itself a perceptual and cognitive construction rather than a direct readout of anatomy, is the other side of the same coin: gender-affirming interventions can be understood as bringing the perceived and represented body into register with the identity, reducing the discrepancy the person carries (Coleman et al., 2022). Read this way, the topic is continuous with the wider study of self-representation, the integration of interoceptive and exteroceptive signals into a sense of the embodied self, and the emotional consequences of prediction error between what the self-model expects and what the world returns.

Current Directions

Contemporary work is concentrated in three areas. The first is the consolidation of clinical guidance: the eighth version of the Standards of Care extended its evidence review substantially and, for the first time, addressed the full lifespan and the specific needs of adolescents and non-binary people, marking the maturation of gender-affirming care into an evidence-graded specialty (Coleman et al., 2022). The second is outcomes research, particularly on adolescent care, where studies linking the timing of intervention to later mental health have begun to supply the longitudinal evidence the field long lacked, even as the samples and designs continue to be debated (Turban et al., 2020). The third is the endocrinology of transgender medicine, which has developed into a coherent subdiscipline with protocols for hormone regimens, monitoring, and the management of long-term health that earlier generations of clinicians improvised (T'Sjoen et al., 2019). Cutting across all three is a continuing effort to understand mental-health disparities not as intrinsic to a gender identity but as consequences of stigma and barriers to care, a reframing that has reshaped both the research questions and the services built around them (Dhejne et al., 2016).

Common Misconceptions

A cross-gender identity is a mental illness.

Current classifications reject this framing. The ICD-11 moved gender incongruence out of the mental-disorders chapter entirely, and the DSM-5's gender dysphoria diagnoses the distress that may accompany incongruence, not the identity itself (Reed et al., 2016).

Transsexualism has a single proven biological cause.

No single cause is established. Neural studies show measurable correlates and support a prenatal-differentiation hypothesis, but the findings are correlational and drawn from small, heterogeneous samples (Guillamon et al., 2016).

There is one true prevalence figure for the condition.

Estimates differ by one to two orders of magnitude depending on ascertainment: clinic-based counts are low, population self-report far higher, and the two measure different things (Arcelus et al., 2015; Zucker, 2017).

Glossary

Cisgender.

Describing a person whose gender identity matches the sex they were assigned at birth; the complement of transgender.

Gender dysphoria.

The DSM-5 diagnosis defined by clinically significant distress arising from a marked incongruence between experienced gender and assigned sex; the diagnosis is of the distress, not the identity.

Gender identity.

A person's internal sense of being male, female, both, or neither; established early and highly resistant to change, and distinct from biological sex.

Gender incongruence.

The ICD-11 term for a marked and persistent mismatch between experienced gender and assigned sex, classified under conditions related to sexual health rather than as a mental disorder.

Gender role.

The set of behaviours, presentations, and social expectations a culture associates with a given gender; a term introduced in the mid-twentieth-century sexology from which the modern concepts grew.

Gender-affirming care.

The range of social, psychological, hormonal, and surgical interventions that support a person in living in their experienced gender and relieve associated distress.

Natal sex.

The sex assigned at birth on the basis of observed anatomy; also called assigned sex, and distinguished throughout from gender identity.

Prenatal sexual differentiation.

The developmental process by which the body and brain acquire sex-typical features before birth, hypothesized to proceed on partly separate timetables for genitalia and brain.

Puberty suppression.

The reversible use of gonadotropin-releasing hormone analogues in adolescents to pause the development of secondary sex characteristics and allow time for assessment.

Sex reassignment surgery.

Surgical procedures that alter the body's sex characteristics to align them with a person's experienced gender; one component of gender-affirming care for some people.

Sexual differentiation of the brain.

The emergence of sex-typical differences in brain structures such as the hypothalamus; central to the prenatal hypothesis about the origins of gender identity.

Standards of Care.

The clinical guidelines of the World Professional Association for Transgender Health for the assessment and treatment of gender incongruence and dysphoria, now in their eighth version.

Transgender.

An umbrella term for people whose gender identity differs from their assigned sex, of whom those seeking full medical transition are one part.

Transsexualism.

The historical clinical term, retained as a MeSH descriptor, for a persistent cross-gender identity accompanied by a wish to alter the body to match it.

Key Researchers

Harry Benjamin (1885-1986). German-American endocrinologist and sexologist whose The Transsexual Phenomenon (1966) gave the condition its first systematic clinical description and its name, and who argued for medical transition over attempted conversion. Wikipedia - Wikidata

Peggy T. Cohen-Kettenis (contemporary). Clinical psychologist, formerly of the Amsterdam gender clinic, who established the Dutch protocol for adolescent care and reviewed the etiology, diagnosis, and treatment of the condition. ORCID - Wikidata

Cecilia Dhejne (contemporary). Psychiatrist and sexologist at the Karolinska Institutet whose Swedish register cohort study of long-term outcomes and review of mental health in gender dysphoria are widely cited. ORCID - Faculty page

John Money (1921-2006). New Zealand-American psychologist at Johns Hopkins who introduced the term gender role and helped establish the distinction between biological sex and gender identity; his work remains controversial. Wikipedia - Wikidata

Robert J. Stoller (1924-1991). American psychoanalyst at UCLA who developed the concept of gender identity and its separation from biological sex, providing the conceptual foundation of the field. Wikipedia - Wikidata

Dick F. Swaab (contemporary). Dutch neurobiologist whose group reported a sex difference in the hypothalamic BSTc and its relation to gender identity, advancing the prenatal brain-differentiation hypothesis. ORCID - Wikipedia - Wikidata

Kenneth J. Zucker (contemporary). Psychologist and long-time editor of Archives of Sexual Behavior whose work on the epidemiology of gender dysphoria clarified how prevalence depends on ascertainment. ORCID - Wikipedia - Wikidata

Frequently Asked Questions

What is transsexualism? Transsexualism is a historical clinical term for a persistent and marked incongruence between a person's experienced gender and the sex assigned at birth, accompanied by a wish to live as the other gender and often to alter the body to match. It is retained as a MeSH descriptor but has been superseded in clinical practice (Benjamin, 1966).

How is transsexualism different from gender dysphoria and gender incongruence? They name the same broad area under different frameworks. The DSM-5 replaced the older diagnosis with gender dysphoria, which diagnoses distress rather than identity, and the ICD-11 uses gender incongruence, which it classifies outside the mental-disorders chapter (Reed et al., 2016).

Is a cross-gender identity considered a mental disorder? Not in current classifications. The ICD-11 removed gender incongruence from the chapter of mental and behavioural disorders, and the DSM-5's gender dysphoria locates any disorder in accompanying distress, not in the identity itself (Reed et al., 2016).

What causes a cross-gender identity? No single cause is established. The leading biological hypothesis is that prenatal sexual differentiation of the brain can proceed differently from that of the body, and neural studies report correlates consistent with this, though the evidence is correlational (Guillamon et al., 2016).

Why do prevalence estimates vary so much? Because they measure different things. Counts from specialist clinics are low, on the order of a few per hundred thousand, while population self-report surveys are far higher because they capture people who never present for treatment (Arcelus et al., 2015; Zucker, 2017).

What does gender-affirming care involve? It spans social, psychological, hormonal, and surgical support aimed at relieving distress and helping a person live in their experienced gender. The Standards of Care of the World Professional Association for Transgender Health set out the current framework (Coleman et al., 2022).

What is puberty suppression and why is it used? Puberty suppression uses reversible gonadotropin-releasing hormone analogues to pause the development of secondary sex characteristics in adolescents, giving time for assessment before any irreversible step; access to it has been associated with better mental-health outcomes (Turban et al., 2020).

How does transsexualism relate to cognition? Gender identity is a component of the self-concept, a stable cognitive representation of who one is, and the associated distress reflects a mismatch between that representation and the perceived body that the mind cannot easily revise (Stoller, 1964).

References