I mentioned this with each post. It's a legal thing, not ethical thing.
The law is where it becomes reality in a societal sense. One could debate the philosophical aspects of "rights," but when the law gets involved that's where we have to act in terms of applying treatments.
The Supreme Court set the bar very low as to what is a right concerning healthcare for inmates. I did not make the decision. They also allowed for Japanese Americans to be placed in internment camps and people with an intellectual disability to be sterilized. The latter case was
Buck v. Bell where the usually highly-respected Oliver Wendell Holmes a Supreme Court Justice notoriously stated, "Three generations of imbeciles are enough, " and allowed for people to be sterilized against their will, and they accepted that eugenics was an acceptable science despite that what was then known has now been proven to be bogus. Only one Justice dissented with the decision. No later generation of the Supreme Court ever apologized or retracted for that prior court's ruling, and in fact it has even been used as a precedent in later major cases further bolstering the vulgarity of what was a terrible decision without attempting to rectify a dark chapter of it's own history.
http://en.wikipedia.org/wiki/Buck_v._Bell
One could argue the ethics of allowing an inmate to acquire hormonal therapy. I, for one, would actually be for someone getting the hormonal therapy. But is is a legal right? No.
But, agreeing with you that the court could make a more enlightened decision in the future, based on previous cases, they'll likely have to answer the following before they ever backed up hormonal treatment. 1) Is there a recognized disorder here?-Yes, that's black and white.
2) Is there a generally accepted treatment that has strong evidence to back it's use for treatment? No, but let's say it's the future, more data comes out and accepted treatments do become available...this leads us to 3) Does the prisoner have the right to acquire hormonal treatment? Under the previous case I mentioned-no.
One possible legal avenue of attack to allow prisoners to acquire such a treatment is under the Americans with Disabilities Act (ADA), that does protect inmates, the law states that to withhold someone something available to others based on a "major life function" be a violation. If the court was convinced that feeling appropriate as to your gender was a "major life function," then there is room for legally allowing treatment as a right. Either that or they would have to overturn the previous legal decision. It's been done before, but only when a new case comes out that forces them to challenge a previously answered question.
....that's beauty of america. 
