My wife and I decided to tell her parents about my gender issues, and they were surprisingly very supportive. The flip side is that my wife strongly feels that I should tell MY parents over Thanksgiving... I'm scared, but I know that it is probably the right thing to do.
It is great to know that even my in-laws can be understanding and supportive though... It's also nice that my wife is encouraging me to come out to people in my life, rather than keep this bottled up.
You are very lucky to have two voices speaking for you rather than one.
I hope all of your future discussions on this matter are successful.