Do you call people by their first names? Even when they are older than you? Even when they are respected more than you? Even when they have a higher education than you do? I do. After all, aren't "all men created equal"? I don't address anyone as Mr or Mrs, and I don't expect anyone to address me as Miss or Ms. I think that we have first names for a reason. :)
I have a short story to tell on this subject. As kids my brothers and sisters and I would always call our neighbors - who were married to each other - Jim (name changed, haha) and Mrs. Jones (name changed, haha), I don't why or when we started calling them that, but the really strange thing was... my sister had called the wife Mrs. Jones to her face once and she had told her "you can call me" Laura (again, name changed) - so why in the world do we - to this day - call her Mrs. 'Jones'?!