I need to come out to my parents but I have got to have the worst kind of nervous reaction to speaking with someone about something serious. And the thing is I have no problems telling other people how I feel on my gender but when come to my parents I always seem to choke. I think part of the problem is that I know my parents wont like it ( I came out to my mom last year and she told me that what I did when I moved out was up to me ). I know that a lot of you probably have or had issues coming out to family including nervousness but how would you handle it if you knew they wont take it well.

Maybe write them a letter?  I haven't come out yet (or even decided if I'm going to), but I have the same problem as you with not being able to communicate in high pressure situations.  A letter would allow you the opportunity to organize your thoughts and present everything properly.