Gender Identity and Gender Expression
'Gender identity' is generally defined as the inner sense of whether someone experiences themselves as a man, a woman, or something else. 'Gender expression' is the outward presentation through clothing, behavior, and appearance. Both concepts are widely used in contemporary policy documents and healthcare guidelines, but it is important to recognize that they are concepts, not objectively measurable entities. The common assumption—that every person has an inner 'gender identity' that is separate from the body—is a theoretical premise, not a scientifically established fact.
What is gender identity?
'Gender identity' refers to a reported inner experience. For the vast majority of people—usually referred to as 'cisgender' in this terminology—that experience corresponds to their sex. A smaller group experiences a discrepancy and may identify as transgender, non-binary, gender-fluid, or agender. The terminology has expanded considerably in a short period of time; at the time of the DSM-IV (1994), most of these categories did not exist or were barely recognized.
The causes of such a discrepancy have not been established. There is no 'gender gene,' no blood test, and no brain scan that can determine 'gender identity.' An extensive critique of the concept can be found at genderid.nl. Studies reporting brain differences between transgender and cisgender people are small, methodologically weak, and have not proven replicable; moreover, they overlap substantially with the effects of hormone use. The Cass Review (2024) concluded that the evidence for a clear biological basis of trans identity is limited. What is clear, however, is that the number of young people—especially girls—identifying as transgender or non-binary has risen explosively since around 2010. Growing attention is being paid to social-contagion hypotheses such as rapid-onset gender dysphoria and the role of peer and internet influences.
In children who display gender-variant behavior, classic follow-up research (Steensma et al. 2013; earlier studies by Zucker and colleagues) shows that 60–90% develop along a cisgender path later in life if allowed to follow their natural course, often in combination with a homosexual orientation. This phenomenon, desistance, is central to criticism of early medical 'affirmation': affirming a trans identity in a child may disrupt this natural course.
What is gender expression?
Gender expression is a far less controversial concept: it simply describes how someone dresses, behaves, and presents themselves. The fact that this does not strictly follow sex is self-evident—men with long hair, women in workwear, and children with cross-gender preferences exist and have always existed. What is disputed in the current debate is the step in which atypical gender expression is interpreted as evidence of an underlying atypical 'gender identity'—an interpretation that does not hold up in many cases.
Gender expression is strongly shaped by culture and time. What is considered 'masculine' or 'feminine' is constantly shifting; this points more toward cultural flexibility than toward the existence of a fixed inner gender essence.
The distinction between identity, expression, and orientation
Identity, expression, and sexual orientation are strictly separated in current terminology. This is logical in theory but less clear-cut in practice: many boys who later turn out to be gay display feminine gender-expressive behavior in childhood, and vice versa. An overly rapid 'gender-affirmative' interpretation of such behavior risks effectively medicalizing gay and lesbian young people—a concern explicitly raised in Iran, as well as in Western contexts, by both LGB organizations and clinicians such as Susan Bradley.
Gender identity and mental health
Young people who identify as transgender disproportionately often have comorbid mental health problems: autism (substantially overrepresented), depression, anxiety, eating disorders, and trauma. Whether gender dysphoria is the cause, consequence, or symptom of these problems is often unclear. An overview of alternative explanations for gender-related doubts among young people can be found at transgendercheck.nl. Further information offered by that site, including a 50-question questionnaire, is available in the Transgendercheck.nl profile. The Cass Review pointed out that at the British Tavistock clinic, this comorbidity was often brushed aside in order to proceed to medical pathways, while psychotherapeutic exploration was barely undertaken. See: Cass Review (2024) and the Cass Review page.
The frequently cited suicide figures—used in the 'transition or suicide' rhetoric—are not empirically tenable as an argument for medical intervention. Research after the closure of the GIDS clinic showed that suicide among young people on the waiting list was extremely rare; the Cass Review described the use of suicide rhetoric as harmful and unsupported by evidence.