BelovedFool
I'm wondering where the line is. I'm partly on the side of personal responsibility with adults, although again, some are vulnerable, some aren't. Who decides? At the moment, it seems to be the individual, and it seems to be "whatever you want".
To me, when we are talking about medical treatment, this comes down to a point about medical ethics. If an intervention is considered to be therapeutically effective and safe, then the standard consent process should apply. But if there isn't evidence that the intervention is beneficial, or if there is evidence it is harmful, then it shouldn't be offered. The exception would be an experimental treatment as part of a controlled trial - in that case patients can consent only as part of the research process and with the added expectation for the research team to rigourously evaluate outcomes.
I haven't thought so much about non- therapeutic, cosmetic body modification - things like tattoos, cosmetic surgery, non-therapeutic male circumcision, possibly even getting a haircut). I don't think the legal position is completely consistent on these, but in general:
- these aren't offered for free on the NHS, or are offered only in very limited circumstances (breast reduction because of chronic pain maybe?) because there is no therapeutic benefit.
- individuals can consent to interventions for themselves and parents can sometimes consent on behalf of their children (ear piercing / haircut ok provided child assents, tattoos not ok). But a practitioner should be aware of when a client does not actually have capacity to consent to what they are asking for (eg severe mental illness)
- individuals aren't considered able to consent to things that are purely harmful (like being killed and eaten / assaulted during sex, or extreme body modification). So having a signed consent form isn't a defence against GBH charges if you do these things - article here has a good summary: theconversation.com/body-modification-when-consent-is-not-a-defence-87816
The difficulty with reassignment surgery is that it's not clearly one thing or another. It's partly cast as a wholly individual choice (like a tattoo - I want this, so I should be able to have it; my body my choice). But it's also seen as a life-saving medical procedure that should be provided by the NHS because of its therapeutic benefits. That's very inconsistent. If it's going to be provided by the NHS there should be demonstrable evidence that it's beneficial not harmful. And if it's a personal choice decision then it certainly shouldn't be freely available, but it also seems far more invasive than other "extreme" body modifications like tongue splitting, which are not legal in the UK.