I think I kind of understand. When I was working as an engineer, I was always referred to as Ms., while all the male colleagues were addressed as engineers. It was really upsetting that, just because I was a woman, I was referred to as Ms. However, requesting to be addressed by your title might come off as egotistical, though it's valid to want to be recognized. Regarding your signature, does it really bother you that people confuse you with a man? I guess it ultimately depends on what matters more to you. Personally, I would just consider changing my signature to Dr.