Category · F60-F69 block
F66 — Psychological and behavioural disorders associated with sexual development and orientation
Terminology note: Sexual orientation itself is not a disorder. F66 (including F66.1, historically termed 'egodystonic sexual orientation') has been substantially critiqued and is not retained in ICD-11. This educational tool teaches its ICD-10 structure while stating this context plainly, and is built specifically to correct — not repeat — this category's most harmful historical misuse.
What is this category?
F66 covers three named presentations: F66.0 (sexual maturation disorder, uncertainty about one's gender identity or sexual orientation during development, causing distress), F66.1 (egodystonic sexual orientation, distress specifically about one's own orientation), and F66.2 (sexual relationship disorder, a gender-identity or orientation difficulty impairing the capacity to form a relationship). As ICD-10 frames it, F66.1 requires that the orientation itself is not in doubt — the classification is about distress, not confusion about what the orientation is.
Core diagnostic concept
The single most important teaching point for this category, and the reason it is included in this build with active correction rather than passive repetition, is this: distress that actually stems from discrimination, family rejection, or internalized societal stigma about one's own sexual orientation is not, by itself, evidence of an F66 disorder. A competent classification exercise should often correctly conclude that no F66 diagnosis is supported, once the actual source of the distress is identified as external rather than intrinsic to the orientation itself.
Key diagnostic features
- Orientation itself is not in question
- F66.1, as ICD-10 frames it, applies only when the person's orientation is not itself uncertain — the classification concerns distress about it, not confusion about what it is.
- Distress must be about the orientation itself, not others' reactions
- Distress attributable to discrimination, family rejection, or internalized stigma is not, by itself, evidence of this classification.
- Not a basis for 'corrective' intervention
- This classification does not support treating a person's orientation as something to be changed; professional ethical guidelines reject that approach.
How to weigh evidence
These learning labels are teaching aids, not official ICD-10 terminology (see Sources and Method).
- supports As ICD-10 frames F66.0/F66.2: genuine uncertainty during development about gender identity or orientation, or a difficulty specifically in forming relationships tied to gender identity or orientation, causing distress.
- consistent not decisive A person mentions their sexual orientation in a clinical history without describing any distress or impairment connected to it.
- raises alternative The distress described is clearly and specifically attributable to family rejection, workplace discrimination, or social stigma, rather than to the orientation itself.
- contradicts or weakens The person's orientation is not in doubt, and any distress present is explained entirely by how others have responded to it.
- missing and necessary to ask Whether any distress described is actually about the orientation itself, or about discrimination, rejection, or stigma — the distinction this category, and this tool, treats as decisive.
Diagnostic boundary
As ICD-10 frames this category, it requires distress specifically about one's own gender identity or orientation, with the orientation itself not in doubt — distress actually caused by discrimination or rejection does not meet this threshold, and often correctly resolves to 'not a disorder' here.
Full comparisons:
Duration and course
Minimum duration: Not fixed by a single universal threshold in ICD-10's description of this category.
Course: Not specifically defined beyond the presence of the described distress or relationship difficulty.
Included presentations
- Sexual maturation disorder: uncertainty about gender identity or sexual orientation during development, causing distress.
- Egodystonic sexual orientation: distress specifically about one's own orientation, which is not itself in doubt.
- Sexual relationship disorder: a gender-identity or orientation-related difficulty specifically impairing the capacity to form or maintain a relationship.
Exclusions and distinguishing presentations
| If this is true instead… | Consider | Why |
|---|---|---|
| Distress that is actually attributable to discrimination, family rejection, or internalized societal stigma, with the person's orientation itself not a source of intrinsic distress | internalized stigma equals disorder | This is this category's single most important boundary: externally-caused distress does not meet F66's threshold, and this presentation often correctly resolves to 'not a disorder.' |
| Confusion or distress specifically about gender identity rather than sexual orientation | F64 | Gender identity and sexual orientation are distinct classification dimensions. |
Four-character subtypes (orientation)
No F66 subcode is taught in depth in this build. A learner should always check whether described distress is genuinely intrinsic to the orientation itself or actually attributable to discrimination, rejection, or stigma — the latter does not support any F66 classification.
- F66.0 — Sexual maturation disorder
- Uncertainty about gender identity or orientation during development, causing distress. (taught for orientation only, not separately assessed in this pilot)
- F66.1 — Egodystonic sexual orientation
- Distress specifically about one's own orientation, not itself in doubt. (taught for orientation only, not separately assessed in this pilot)
- F66.2 — Sexual relationship disorder
- A gender-identity or orientation-related difficulty impairing relationship formation. (taught for orientation only, not separately assessed in this pilot)
- F66.8 — Other psychosexual development disorders
- A presentation not matching the named subtypes. (taught for orientation only, not separately assessed in this pilot)
- F66.9 — Psychosexual development disorder, unspecified
- A presentation identified but without enough information to specify further. (taught for orientation only, not separately assessed in this pilot)
External causes to check first
Categories in this block require that the disturbance is not better explained by another external cause listed below. These short capsules are reminders, not full teaching modules.
Nosological-context capsule — F64, F65, and F66
A shared context note for F64 (Gender identity disorders), F65 (Disorders of sexual preference), and F66 (Psychological and behavioural disorders associated with sexual development and orientation): a person's gender identity and a person's sexual orientation are not, in themselves, mental disorders. These three ICD-10 categories are presented here for classification literacy — to understand how ICD-10 was structured and how later revisions changed it — not as clinical guidance for assessing or treating a real person's identity or orientation.
What to check:
- Source of distress: where a vignette describes distress, is it clearly attributable to the person's gender identity or sexual orientation itself, or is it better explained by discrimination, family or social rejection, internalized stigma, or an unrelated co-occurring condition? The latter does not support any F64/F65/F66 classification on its own.
- What changed in ICD-11: gender incongruence was reclassified out of the mental-disorders chapter entirely (moved to a chapter on sexual health), and 'egodystonic sexual orientation' (previously F66.1) was removed — both changes reflect a shift away from treating identity or orientation itself as pathology.
- What F65 covers: F65 concerns patterns of sexual preference and their behavioural expression, most of which (e.g. fetishism, exhibitionism) are covered here only at classification-title level; this educational tool authors no scenario, case, or exercise content for F65.4 (Paedophilia) beyond its bare classification title, as a fixed editorial line.
- Level of authored depth: F64, F65, and F66 are deliberately covered at classification-orientation depth only in this tool, with no in-depth subcodes and reduced case/exercise coverage, reflecting the sensitivity of this territory rather than any gap in the underlying classification.
Clinical guidance on gender-affirming care, sexual health, or supporting someone experiencing minority stress or discrimination — all of which are outside this capsule's scope and require qualified professional support.
Worked example — recognising when F66 does not apply
A young adult reports significant distress after disclosing their sexual orientation to their family, who reacted with rejection and have since become emotionally distant. The person states clearly that they are not confused or distressed about their own orientation itself — the distress they describe relates entirely to the family's reaction and their fear of further rejection from others.
- Step 1 — Check whether the orientation itself is a source of distress: the person explicitly states it is not.
- Step 2 — Identify the actual source of distress: family rejection and fear of further rejection — an external, social cause.
- Conclusion — No F66 classification is supported here. The distress is genuine and significant, but it is attributable to discrimination and rejection, not to the orientation itself, and this presentation is correctly classified as not meeting this category's threshold.
Interactive practice
- Type B Distress, but not from the orientation itself Boundary discrimination · Transfer
Retrieval prompts
Try answering each of these from memory before revealing where to check. Nothing you think or type here is sent or saved anywhere.
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Explain the single most important check to make before applying any F66 subtype.
Reveal answer location
Check Duration and course, Diagnostic boundary, or the rapid revision card below — the cue you need is one of those, in this category's own already-authored wording.
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State why F66 does not support treating a person's orientation as something to be corrected.
Reveal answer location
Check Duration and course, Diagnostic boundary, or the rapid revision card below — the cue you need is one of those, in this category's own already-authored wording.
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Explain why distress caused by family rejection does not, by itself, meet F66's threshold.
Reveal answer location
Check Duration and course, Diagnostic boundary, or the rapid revision card below — the cue you need is one of those, in this category's own already-authored wording.
These self-checks are a personal study aid only, visible to you on this page for this visit — they are not stored and do not affect your mastery dimensions.
Rapid revision card
F66: F66, as ICD-10 frames it, requires distress intrinsic to one's own orientation, not distress caused by discrimination or rejection — which often correctly resolves to 'not a disorder.'
Decisive boundary cues:
- Distress genuinely intrinsic to uncertainty or discomfort about one's own orientation, orientation itself not in doubt for F66.1 -> as ICD-10 frames it, may meet this category's threshold.
- Distress clearly attributable to discrimination, rejection, or stigma -> does not meet this category's threshold; often correctly 'not a disorder.'
- Confusion or distress about gender identity rather than orientation -> see F64 instead.
Duration/course: Not specifically defined beyond the presence of the described distress or relationship difficulty.
Nearest alternatives: f64, f65
Common mistake: Treating distress caused by discrimination or family rejection as evidence that a person's orientation itself needs addressing.
Retrieval prompt: Is any distress described here actually intrinsic to the orientation itself, or caused by how others have responded to it?
(or use your browser's print function) Open full-page printable revision view →
Related glossary terms
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Minority stress
Chronic, socially-based stress experienced by members of a stigmatised minority group (such as discrimination, family or social rejection, or internalized stigma related to sexual orientation or gender identity), which can itself produce genuine psychological distress. Relevant to correctly distinguishing distress caused by minority stress from any implication that a sexual orientation or gender identity is itself a disorder (F66).
Source basis
WHO ICD-10 international classification structure and code/title (ICD-10 Browser, 2019 English release).
Original educational synthesis, informed by general published clinical-education understanding of ICD-10 F60-F69; no verbatim CDDG or DCR text is reproduced. See Sources and Method for the full policy.
Last reviewed: 2026-09-17. Full policy: Sources and Method.
Educational resource only. This page and its cases teach ICD-10 classification reasoning using fictional scenarios. It does not diagnose real people and should not be used to assess yourself or anyone else. A person's gender identity or sexual orientation is not itself a disorder. If you or someone you know is struggling with a pattern of behaviour, an urge you find hard to control, or distress related to discrimination or how you are treated by others, please seek prompt, respectful professional support.