No knowledge of the sexes

Let me preface this by saying when I want to refer to my kids I'll just refer to them by the first letter of their names. So my son is S and my daughter is B.
Yesterday I was playing with my baby girl, and asking, "Who's a pretty girl?" With my boy I've always said, "Who's a handsome boy?" and he would respond with his name, "S". I guess I had my first birds and bees conversation with him trying to explain to him that his sister is a girl and he is a boy. You might be wondering why, so here is the story behind it.
When I would say, "Who's a pretty girl?" he would respond, "S". I would then respond, "No, your sister is a pretty girl. You're a handsome boy." So I would ask, "Who's a handsome boy?" and he would say, "S". Then I would ask, "Who's a pretty girl?" and he would say "S". I would try to correct him and say, "No B is a pretty girl, you're a handsome boy", and would ask the question again and he would respond with B. But if I were to ask again he would say "S". After several minutes of trying to explain to a two and half year old the difference, I finally decided it probably couldn't be done at this point in the game. So we stopped playing the game of "Who's a pretty girl?" and "Who's a handsome boy?" Although I don't think he was done playing, because he kept on saying, "B pretty. S pretty." over and over again.
So I'm proud to say I had my first birds and bees conversation, they say it's never too early. Although it didn't go well. So maybe better luck next time.