Its very difficult to finally "come out" to your parents.. it was for me anyway,. When I 'did' tell her, she kind of all ready 'knew' that there was some thing about me, knowing I had problems and issues through out my life. My mother is OLD school, ok ? she just knows about gays and lesbians, she didn't really get the whole "I am a women in a man's body" thing. So basically, depending on how knowledgeable your parents are, and how much they understand medical matters, is probably how you should genitally explain it all - if you have to go that far into it. She just really thought I was gay or some thing.. So I had to explain it and by the end of that was in a right state for an hour crying about it to her. As far as she 'knew' Women are Women, and men are men, and those who act like women or what ever, are gay, effeminate, what ever, and Lesbians, well, lol you get the idea ? Some people really don't get it, and considering the fact its your parents, and they "really" need to know, you will be actually surprised at their responses, like my mum, yep she "knew" that I was kind of a girl, - if not exactly completely the right understanding of things, but it did make me smile, with some kind of relief, but really did help to clear the air. At least I could tell her, no mum, I am not "gay" I am a girl, in a boys body, etc. The weird thing about all this parents really 'do know' lol, you think you can fool them, or they really don't see what's going on, or how your behaving etc, but yeah they would have to be 'really' blind not to know those things otherwise. Your their baby after all, and they are always concerned with your welfare.
Anyways. Not long after, I was just being myself, but this time openly hanging up "female" clothes in my bed room, not worried about being questioned any more or looked at weirdly. Notice here I said nothing about my dad, ? well yeah I am from a divorced family, and actually have no idea if my dad knows at all about me.

(Not that it matters) That's my little story, sorry for the long reply !
Catherine.