I’m looking for examples for something I’m writing. Trans people are diagnosed as trans based on not much more than their say-so. There are no lab tests, MRIs, CT or X-rays to diagnose it. I don’t think there’s any other medical field in which they cut off your testicles, uterus or any other organ because of the patient’s decision alone.
You can rule out cosmetic surgeries as an example, because trans surgeries aren’t just cosmetics - a double mastectomy isn’t just a breast reduction, for example.
My understanding is that psychiatric surgeries have gone mostly out of style, and while might be performed in some countries still, they’re a very rare edge case.