I answered no, but to be fair I do occasionally call my Dad by his first name. That's only when we're giving each other shit, in that special, funny way that only fathers and sons can do. Or when I need to differentiate between Dad (my Grandfather) and Dad (my Dad) when talking to my Grandma, since she always calls my Grandfather "Dad". To be fair, she often calls me by my uncle's name, and mixes up her kids quite a bit. My Mom, I would never dare call her by her first name directly. I haven't had the best relationship with my Mom, but I would never call her by her first name. Seems like it shows a complete lack or respect for the people who raised you. Except for my Dad, if he gives me shit, I'll give it right back with a smile.