I like John’s advice best.
Of course, in my HEAD I’d be tempted to call him, “the boy” every time he referred to me as “the girl.” As in talking to the boss and saying “the boy needs training” or if he does something well say, “that’s a good boy.” Or when mail comes, “that goes in the boy’s in box.”
There was one man I worked with closely at one time who knew exactly who I was, and yet continued to call me by the wrong name, not even something close to my name. It wasn’t even mean-spirited so much as he just viewed me as so far below him that I was insignificant and not worth taking the time to correct himself. After months and eons of corrections, in which other people would tap his shoulder and say, “Come on, you know her name,” and he would apologize weakly and apathetically, I finally started calling him the wrong name. His name was Michael and I kept calling him Stan. He’d continue to see me in the hallway and say “Hi, wrong name” and I’d say, “Hi Stan,” and so on and so forth. On his birthday card in the office, I said “Happy Birthday, Stan! Love, Wrong Name.”
At my current job I prefer to be called by my longer name (my name can be shortened) and this one guy told me he thought it was stupid and so hence kept calling me by the short name in a very purposeful way. Well, good news for me, his name is Richard and prefers to be called thusly, so whenever he shortens my name I refer to him as “Dick” which he hates. After a few rounds of being referred to as “Dick” he shaped up and started calling me by my right name. Actually, now we get along famously, and joke around a lot, and whenever he slips to calling me by my shortened name I just smile at him and say, “Dick” and he laughs.