There's a very small portion of the population that appears to actually suffer from so-called gender dysphoria. In these cases an argument can be made for gender reassignment surgery and hormone treatment, but only for adults. Regardless there is no strong evidence that such treatments actually improves the well being of the patient in the longer term. In fact the opposite appears to be the case in the majority of cases. Therefore this should not be considered a public health issue nor paid for using tax dollars. However since we're talking adults here then they should be given the freedom to make their own life choices. In essence if you want to cut your dick off then have at'er, but don't expect me to pay for it or be sympathetic if it does not turn out the way you hoped. I wish you all the best but you are on your own here.

Otherwise the arguments in support of gender reassignment are, every one, emotion based and therefore can be discounted in any serious discussion about public health policy.