F64 vs F66
F66 — Psychological and behavioural disorders associated with sexual development and orientation
Distinguish content genuinely concerning gender identity (F64) from content concerning sexual orientation and orientation-related distress (F66) — two distinct areas that ICD-10 classified separately but that are frequently and inaccurately conflated with one another.
This is just for your own thinking. It is never submitted, sent, or stored anywhere — it disappears the moment you leave or reload this page.
Show overlap — what both share
Both categories sit within the same historical grouping and both concern identity- or orientation-related classification that ICD-11 has substantially revised.
Show decisive evidence
- F64 concerns a person's experienced gender in relation to the sex assigned at birth — gender identity.
- F66 concerns sexual orientation and psychological or behavioural disorders historically associated with it — a separate dimension from gender identity.
- Checking which dimension a vignette is actually describing (gender identity vs. sexual orientation) is the decisive step, since the two are conceptually distinct and are not interchangeable.
- Neither classification should be applied on the basis of identity or orientation alone; both require checking whether the presentation is genuinely about classification-relevant content at all, given this tool's deliberately limited scope for both categories.
What weakens F64: Content specifically about experienced gender in relation to sex assigned at birth favours F64; content specifically about sexual orientation and any associated distress favours F66.
Show duration / course
Not duration-based; the decisive factor is which dimension (gender identity vs. sexual orientation) the content actually concerns.
Show exclusions / context
Gender identity and sexual orientation should never be treated as the same dimension or conflated with one another when working through either category.
Show information still needed
Whether the vignette concerns gender identity specifically, or sexual orientation specifically.
Show the common trap
Conflating gender identity and sexual orientation as though they were the same dimension of classification.
Mini challenge — practise this distinction
Apply the discriminating evidence above to a fresh case before checking the full feedback.