Well, it's pretty common knowledge that hormones will work better the earlier you take them. If you waited until finishing medical school, you would probably miss the window of opportunity for hip development, and things like male pattern baldness may rear their ugly head (depending on your genetics). On the other hand, having the money from the kinds of jobs you could get after going to medical school would make transition a lot easier, assuming transitioning on the job wasn't a problem. But what are these bylaws that you are talking about? If they are something that would prevent you from transitioning while in medical school, wouldn't that be discrimination?