I wrote this as a response to another thread so sorry if it's not the best answer for you but it touches on medical ethics:
Let’s look at this from a medic ethics perspective. Here are four of the basic principles that help inform medical decision making:
Beneficence - acting in the patient’s best interest
Non-maleficence - do no harm
Autonomy - the patient’s right to refuse/choose their treatment
Justice - the fair sharing of resources
Its helpful to look at this through an NHS lens as 4 actually helps how we judge the first 3.
There are always conflicts of beneficence vs autonomy - a patient wants something that is not in their best interest. As long as you have capacity patients are within their rights to choose what is not good for them. However this normally always applies to refusal of treatment, not receiving of treatment. You can refuse an appendectomy you may need (for example) but you can’t demand one you don’t need. This is why I think its helpful to use an NHS way of looking at things as in countries where private healthcare is more abundant the autonomy/justice conflict is more blurred.
Non-malificence - that plays into the not performing an appendectomy that is not needed decision, as does justice. However it is not absolute, patients undergo harm all the time. Chemotherapy for example. Or say there is only one doctor on a ward, one patient has a headache and wants paracetamol prescribing, one is having severe chest pains and might be having a heart attack. We can (probably!) agree it is ethical to leave the patient with a mild headache in pain while the heart attack is treated, even though it is doing that first patient ‘harm’. Or stable, elective patients that have their surgery delayed due to emergencies. This also comes back to a share fairing of resources.
Why don’t we do cosmetic surgery on the NHS? People may want it (autonomy) and it may make them feel better (beneficence). However it has inherent risks that outweigh the benefit (non-malificence) and has been decided not to be a fair use of resources when there are waiting lists/restrictions to treatment for physical illnesses. There is obviously an argument about risk vs harm of cosmetic surgery if someone is unhappy with a body part but this is the current position of the NHS. Or is it? Breast reconstruction is offered after a mastectomy for cancer for example. No one needs implants under their skin for their organs to function correctly. What is so different about this situation to an 18 year old girl who would feel happier with bigger boobs?
For all the principles you will likely find an ‘anomaly’ you could reasonably argue against.
Ethics aside, surgical treatment for gender dysphoria is a psychiatric anomaly. There are physical treatments for psychiatric disorders - vagus nerve stimulators, ECT for depression for example and all psychiatric drugs try to change physiology in some way. However this would be the only current surgical treatment of a psychiatric disease (I think!), even those that involve physical delusions/symptoms etc. Patients with functional neurological disorders have symptoms that are real, but their belief in the cause of those symptoms is not always correct (understandably). Some believe they have a tumour causing their symptoms despite no evidence of one, they should not be treated as if they have a tumour and offered surgery, it wouldn't be in their best interests or avoid harm. It’s why psychiatrists aren’t surgeons. Well maybe what is happening with gender dysphoria is just an advancement in medicine? Except it is a healthy body. It would be the first non-cosmetic surgery carried out on a healthy body with an aim to cure a disease (even prophylactic mastectomies etc are done on the basis of a gene test showing increased risk of cancer). There is nothing wrong with the physical organs of a person experiencing gender dysphoria. But if it makes them happier what’s the harm? Well exactly. Does it fall under treating them in their best interests? Does it fall under doing no harm? Does it fall under justice? Does it even fall under autonomy if you doubt their ability to make an informed decision? Are they currently experiencing a mental disorder that informs their decision making? How do we answer these questions? Evidence. I don’t believe we have the evidence to answer those questions.
I would argue ‘happiness’ is not good evidence. People struggling with anorexia can report being much ‘happier’ at extremely low weights and would fight every suggestion otherwise. People with addictions can find life much harder without their substance. Manic episodes can feel extremely thrilling. However if you value autonomy then in these situations you could argue - well crack on then. It’s your body. If self-harm helps you cope then carry on. If starving yourself gives you a sense of control that you feel you need then off you go. We have to ask ourselves why we don’t take this approach in these situations but should or shouldn’t in gender dysphoria.
We also have to be careful about ascribing ‘happiness’ post-surgery to the surgery itself. Maybe having gender reassignment surgery is an ‘end of the road’ type situation. There is nowhere further to go. It forces a state of acceptance. Is it the acceptance itself that can lead to a lowering of overt distress? And importantly, is there a less harmful alternative? Is there another road to acceptance? There is evidence that allowing people with gender dysphoria to go through puberty, with support and to live their lives can ease dysphoria. Is the cause of gender dysphoria in middle aged males the same as in pre-pubescent girls? Or children? Should the treatment be the same?
Is it a mental disorder at all? If not, why not? If not, are we mischaracterising other mental disorders? Should all the treatment be cosmetic? And done privately in the UK? Then only people with the funds could afford gender reassignment. But is that ok if its just an aesthetic choice like buttock implants? Or is it unethical as people with less resources could experience more distress. But that would take us back into the realms of a mental disorder...
Is it like sexuality? If not, why not? If it is surely the NHS should have no involvement whatsoever.
Why is paedophilia not treated as a valid sexual preference the world just needs to accept? Where do we need to challenge the ‘accepted norm’ and where is there validity in widely held societal beliefs?
My personal take on it is gender dysphoria has a lot more in common with other mental conditions than with a sexuality and I have yet to see the evidence for why it should be treated so differently. And not just in terms of medical/surgical treatment, but in terms of medical ethics, safeguarding, Gillick competence, consent, affirmation, legal recognition etc. I believe if the evidence is missing then the medical profession should not proceed on ‘assumptions’ in the mean time.
Autonomy can’t trump all here. The medical and surgical treatments are not benign or reversible. The surgery itself does not make a vagina, or a penis. These people do not become the other sex. They live with a facsimile which has inherent risks to their physical and mental wellbeing which you can’t address through psychotherapy etc. I really feel this fact seems to be forgotten.
I do not have the answers. I think we need much more evidence before we can unpick this more intelligently, but I believe while we don’t have the answers it is not ethical to carry on as we are.