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.