This isn't exactly biological family... But, one of my best friends from my old high school, in what I could consider my family of friends, posed an extremely awkward question at the time (especially the way he phrased). I had just revealed only 15 minutes earlier that I was trans, and he said to me:
"Hmmmm... Well it is not like you want to have a vagina or anything and have sex with men?" He then lets out this awkward laugh, and the tone he said this in implies he would not accept a "Yes" answer. I was actually so shocked I kind of switched subjects at that point to talk about how long I have been consciously having these feelings (which has been 18 years). After that, I realized I didn't want to share much more of my feelings at that time. In reality, of course I want a vagina and to have sex with it, but that is not my sole motivation! Knowing my friend, he would have construed my feelings as being a fetish rather than a genuine feeling of dysphoria. I think his preconceptions of being transgender were off. One day, I will explain more to him but for now I realized how he has to come to terms with me.