How Can I Be Sure Myself, or My Child, or My Patient, Is Trans?
The questions that matter most, answered honestly, using the world’s leading medical guidelines as our guide.
These are the questions that sit quietly at the centre of so many conversations. A parent watching their child, wondering what they are seeing. A person lying awake, trying to make sense of feelings they have carried for years. A doctor in a consultation room, wanting to get it right and not quite knowing where to start. Nobody asks them out loud very often, because they feel too big, or too risky, or too close to home. So let me ask them here, and let me answer them as honestly as I can, using the world’s leading medical guidelines as our guide.
How do I know if someone is definitely trans?
The honest answer is that there is no single test, scan, or blood result that will give you a definitive answer, and that is true for many things in medicine. What the international guidelines ask us to look for is a strong and lasting sense that the gender a person feels themselves to be does not match the sex they were recorded as at birth.
Strong means it is significant and meaningful in their life, not a passing thought or a brief phase of exploration. Lasting means it has been there across time and across different situations. When a person consistently and clearly tells you who they are, in different settings and in different relationships, that is exactly the kind of evidence these frameworks are built upon.
The world’s major medical organisations, including the World Health Organisation, the American Psychiatric Association, the World Professional Association for Transgender Health, and the Endocrine Society, are all agreed on this. The starting point is always the person’s own experience of themselves.
How long should the feelings have been there?
The different guidelines give slightly different guidance here. The DSM-5, which is the American psychiatric diagnostic manual, requires at least six months. The ICD-11, which is the World Health Organisation’s classification system and the one used across most of the world, asks for several months in adolescents and adults, and around two years in children. WPATH, the international professional body for transgender healthcare, does not name a specific duration but asks that the feelings are sustained.
What matters clinically is not reaching a fixed number of months, but rather that the feelings are not fleeting and that they have been present long enough to be confident they reflect something real and enduring about that person’s identity. A good clinician is not counting calendar months. They are listening carefully, over time, to what someone is telling them about themselves.
What if they have changed their mind at times?
This is one of the questions I hear most often, and it deserves a careful answer. The key question is not whether the feelings have fluctuated, but what exactly is fluctuating.
There is a real difference between someone who is questioning whether to accept their gender identity, perhaps because they are worried about what it means for their life, their relationships, or how others will see them, and someone whose actual feelings of gender incongruence genuinely come and go.
The first is incredibly common and completely understandable. Working out whether you are trans, and then deciding what to do about it, can be a long and sometimes uncertain process, and that uncertainty is not evidence that the identity is not real. What the guidelines ask us to look at is whether the underlying feeling of being a different gender from the one assigned at birth is consistently there, even when the person is wrestling with what to do about it.
If the feelings themselves truly go away for sustained periods, that is worth exploring carefully and kindly. Doubt, fear, and hesitation are not the same as the feelings disappearing.
Very often, what looks like uncertainty from the outside is actually someone trying to find their courage, or trying to protect themselves from a world that has not always been kind to people like them.
How can I be sure? And what about mental health?
You may never be entirely certain, and that is something clinicians need to sit with honestly. Medicine rarely deals in certainties. What we have are frameworks that ask us to listen carefully, take a thorough history, and consider a person’s wellbeing as a whole.
The guidelines do ask that any mental health difficulties a person may also be experiencing are understood and supported, but this is important to be clear about: having mental health difficulties does not mean someone is not trans, and it is not a reason to withhold care.
In fact, a great deal of the mental health distress that trans people experience is a direct result of gender dysphoria itself, and it often improves significantly with gender-affirming care. The research on this is clear and consistent. Supporting someone’s mental health alongside their gender care is about making sure they are in the best possible place to make decisions, not about using it as a reason to delay or deny treatment that could help them.
Is it OK to go on someone’s self-reported feelings?
Yes, and not only is it acceptable, it is essential. Listening to what a person tells you about their own experience of gender is the starting point in every major international guideline. There is no external test that can tell you more about a person’s inner sense of who they are than they can themselves.
That does not mean we skip a careful clinical conversation. It means we take what we are told seriously, ask thoughtful questions, and build a full picture over time. The ICD-11 is very clear on this: the diagnosis is based on a strong and lasting mismatch between the gender a person knows themselves to be and the sex they were recorded as at birth. The person living that experience is the primary, and often the only, source of that information.
This is not unusual in medicine. We go on self-reported pain. We go on self-reported mood. We go on self-reported experience in a great many clinical situations. Gender is no different.
At what age can I confidently say someone is trans?
There is no minimum age, but there is appropriate care and caution at different stages of a child’s development. Children as young as three or four years old can begin to express a gender identity that is different from the sex they were assigned at birth, and the World Health Organisation’s ICD-11 recognises this formally under the category of gender incongruence of childhood.
What changes with age is not whether the identity is real or valid, but what support and treatment might be appropriate. Helping a child use a different name, different pronouns, or dress in a way that feels right to them can be appropriate at any age. Medical treatment, such as puberty blockers or hormones, is considered from puberty onwards and requires careful, supported conversations about what it means and what comes next.
Age does not determine whether someone is trans. It shapes how we support them safely and appropriately.
A note on the guidelines
Everything in this article is grounded in the major international frameworks for diagnosing and supporting gender incongruence. These include the DSM-5-TR from the American Psychiatric Association, the ICD-11 from the World Health Organisation, the WPATH Standards of Care Version 8, the Endocrine Society Clinical Practice Guideline, and the American Academy of Paediatrics policy statement.
These are not fringe positions. These are the frameworks that the world’s leading medical organisations have built, tested, and endorsed. They exist to help people get the care they need, and to help clinicians deliver it well. The full diagnostic criteria from each of these guidelines are set out in the reference section below.
For a detailed response to the Cass Review and how it compares with these international standards, read my full analysis here.
If this has been helpful, please share it
Share it with a parent who is worried. Share it with a doctor who is unsure. Share it with a person who is trying to find the words for what they feel. These conversations matter, and the more of us who are having them honestly, the better things will be for everyone.
Reference: The Diagnostic Criteria in Full
The following section sets out the formal diagnostic criteria for gender incongruence from each of the major international guidelines. These are the frameworks that clinicians use when assessing and supporting trans people, and they are the foundation on which everything written above is based.
1. DSM-5-TR: Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, Text Revision
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 5th ed., Text Revision (DSM-5-TR). Washington: APA; 2022. Diagnostic codes 302.6 and 302.85.
Gender Dysphoria in Adolescents and Adults (Code 302.85)
A marked incongruence between one’s experienced or expressed gender and their assigned gender, lasting at least six months, as manifested by at least two of the following:
A marked incongruence between experienced or expressed gender and primary or secondary sex characteristics.
A strong desire to be rid of one’s primary or secondary sex characteristics because of a marked incongruence with one’s experienced or expressed gender.
A strong desire for the primary or secondary sex characteristics of the other gender.
A strong desire to be of the other gender, or of some alternative gender.
A strong desire to be treated as the other gender, or as some alternative gender.
A strong conviction that one has the typical feelings and reactions of the other gender, or of an alternative gender.
The condition must also be associated with clinically significant distress or impairment in social, occupational, or other important areas of functioning.
Gender Dysphoria in Children (Code 302.6)
A marked incongruence between one’s experienced or expressed gender and assigned gender, lasting at least six months, as manifested by at least six of the following criteria. The first criterion listed must be among those present:
A strong desire to be of the other gender, or an insistence that one is the other gender.
In children assigned male at birth, a strong preference for cross-dressing or simulating female attire; in children assigned female at birth, a strong preference for wearing only typical masculine clothing and a strong resistance to the wearing of typical feminine clothing.
A strong preference for cross-gender roles in make-believe play or fantasy play.
A strong preference for toys, games, or activities stereotypically used or engaged in by the other gender.
A strong preference for playmates of the other gender.
In children assigned male at birth, a strong rejection of typically masculine toys, games, and activities and a strong avoidance of rough-and-tumble play; in children assigned female at birth, a strong rejection of typically feminine toys, games, and activities.
A strong dislike of one’s sexual anatomy.
A strong desire for the primary or secondary sex characteristics that match one’s experienced gender.
The condition must be associated with clinically significant distress or impairment in social, school, or other important areas of functioning. Note: gender nonconformity is not in itself a mental disorder. The critical element of gender dysphoria is the presence of clinically significant distress associated with the condition.
2. ICD-11: International Classification of Diseases, 11th Revision
World Health Organisation. International Classification of Diseases for Mortality and Morbidity Statistics (11th Revision). Geneva: WHO; 2019. Codes HA60, HA61, HA6Z. Available from: https://icd.who.int
The ICD-11 classifies gender incongruence not as a mental disorder, but as a condition related to sexual health (Chapter 17). This reflects the current understanding that trans-related and gender diverse identities are not conditions of mental ill-health, and that classifying them as such causes stigma and harm.
HA60: Gender Incongruence of Adolescence and Adulthood
Characterised by a marked and persistent incongruence between an individual’s experienced gender and the assigned sex, which often leads to a desire to transition in order to live and be accepted as a person of the experienced gender, through hormonal treatment, surgery, or other health care services to make the individual’s body align, as much as desired and to the extent possible, with the experienced gender.
The diagnosis cannot be assigned prior to the onset of puberty.
Gender variant behaviour and preferences alone are not a basis for assigning the diagnosis.
There is no requirement for clinically significant distress or impairment. The incongruence itself is sufficient for diagnosis.
HA61: Gender Incongruence of Childhood
Characterised by a marked incongruence between an individual’s experienced or expressed gender and the assigned sex in pre-pubertal children. It includes:
A strong desire to be a different gender than the assigned sex.
A strong dislike of one’s sexual anatomy or anticipated secondary sex characteristics, and/or a strong desire for the primary or anticipated secondary sex characteristics that match the experienced gender.
Make-believe or fantasy play, toys, games, activities, and playmates that are typical of the experienced gender rather than the assigned sex.
The incongruence must have persisted for about two years. Gender variant behaviour and preferences alone are not a basis for assigning the diagnosis.
3. WPATH Standards of Care, Version 8 (SOC8)
Coleman E, et al. Standards of Care for the Health of Transgender and Gender Diverse People, Version 8. International Journal of Transgender Health. 2022;23(Suppl 1):S1-S259. doi:10.1080/26895269.2022.2100644
WPATH SOC8 is the primary international clinical practice guideline for the health of transgender and gender diverse people. Rather than setting rigid gatekeeping criteria, SOC8 provides flexible recommendations that are intended to be adaptable to individual needs and regional contexts. For the initiation of hormone therapy in adults and older adolescents, SOC8 recommends that clinicians confirm the following (Statement 5.3):
The experience of gender incongruence is marked and sustained. 5.3a:
Diagnostic criteria are fulfilled in regions where a diagnosis is necessary to access health care. 5.3b:
Other possible causes of apparent gender incongruence are identified and addressed. 5.3c:
Mental health difficulties the person may also be experiencing are assessed, with risks and benefits of treatment discussed. 5.3d:
Physical health conditions that could affect treatment outcomes are assessed, with risks and benefits discussed. 5.3e:
The capacity to consent to the specific treatment is assessed. 5.3f:
The capacity to understand the effect of gender-affirming treatment on reproduction is assessed. 5.3g:
SOC8 does not require a set duration of real-life experience in the affirmed gender before medical intervention, and removes several previous gatekeeping requirements from earlier versions of the standards.
4. Endocrine Society Clinical Practice Guideline
Hembree WC, Cohen-Kettenis PT, Gooren L, et al. Endocrine Treatment of Gender-Dysphoric/Gender-Incongruent Persons: An Endocrine Society Clinical Practice Guideline. Journal of Clinical Endocrinology and Metabolism. 2017;102(11):3869-3903. doi:10.1210/jc.2017-01658. Co-sponsored by the Paediatric Endocrine Society and WPATH, amongst others.
The Endocrine Society works within the DSM and ICD diagnostic frameworks. For assessment, it recommends (Recommendation 1.1) that diagnosing clinicians should have the following:
Competence in using the DSM and/or ICD for diagnostic purposes.
The ability to diagnose gender dysphoria or gender incongruence and distinguish it from conditions with similar features, such as body dysmorphic disorder.
Training in diagnosing psychiatric conditions.
The ability to undertake or refer for appropriate treatment.
The ability to assess the person’s understanding, mental health, and social circumstances that may affect treatment.
A practice of regularly attending relevant professional meetings.
For initiating gender-affirming hormone therapy, the Endocrine Society recommends confirming:
A persistent, well-documented gender dysphoria or gender incongruence.
Any mental health, medical, or social difficulties that could affect treatment have been understood and addressed.
The individual has the capacity to give informed consent.
For adolescents, sufficient understanding to make a fully informed decision about treatment, which can be demonstrated from the early stages of puberty.
5. American Academy of Paediatrics (AAP)
Rafferty J, AAP Committee on Psychosocial Aspects of Child and Family Health, AAP Committee on Adolescence, AAP Section on Lesbian, Gay, Bisexual, and Transgender Health and Wellness. Ensuring Comprehensive Care and Support for Transgender and Gender-Diverse Children and Adolescents. Pediatrics. 2018;142(4):e20182162. doi:10.1542/peds.2018-2162. Reaffirmed August 2023.
The AAP endorses the DSM-5 definition of gender dysphoria and the WPATH and Endocrine Society recommendations for gender-affirming interventions, within a gender-affirming, nonjudgmental clinical approach. Its key principles are:
Gender identity is shaped by a combination of biological, psychological, social, and cultural factors.
A persistent, consistent, and insistent sense of a gender identity that differs from the sex assigned at birth, sustained over time, is a key clinical signal.
Open-ended exploration of a person’s feelings and experiences should have no pre-defined outcome.
Attempts to change a person’s gender identity through psychological means are harmful and ineffective.
The AAP supports social, legal, medical, and surgical affirmation as part of a comprehensive care model, where clinically indicated.
Key differences across the frameworks
Distress requirement: The DSM-5-TR requires clinically significant distress or impairment. The ICD-11 does not. WPATH SOC8 and the Endocrine Society focus on the persistence and authenticity of the incongruence rather than requiring distress as a precondition.
Duration: DSM-5 requires at least six months. ICD-11 HA60 requires several months for adolescents and adults; ICD-11 HA61 requires approximately two years for children. WPATH SOC8 requires that incongruence is marked and sustained, without specifying a duration.
Classification: The DSM-5 classifies gender dysphoria within its mental disorders framework, while explicitly stating that gender nonconformity is not a mental disorder. The ICD-11 removes gender incongruence from the mental and behavioural disorders chapter entirely, placing it in conditions related to sexual health.
Children: All frameworks distinguish between childhood presentations and adolescent or adult presentations, and require greater caution, a longer observed duration, and specialist multidisciplinary team involvement when treating younger people.