Last night, the family was in a odd configuration in which the boy was in the bathroom, on the toilet, with the door closed and the rest of us were sitting outside. You know that seems to happen sometimes?  Anyway, a conversation ensued which went like this:

Girl: I girl, you (pointing to Eric) boy, mommy girl!

Eric: What about your brother?

Girl: Ummm…boy!

Me: What makes someone a boy or a girl?

Girl: ‘Cause! Just ’cause!

Boy (from inside the bathroom): Hey, girl, let me tell you.  I’m a boy because I have a penis and you’re a girl because you don’t.

Girl: I have penis, too!

Me (yelling through the door): She says she has a penis, too.

Boy (not missing a beat): Well, then, she’s a boy.

Glad that’s been cleared up.