the little girl and the little boy

The little girl: I can't play with you.

The little boy: Why not?

The little girl: Mom said I shouldn't.

The little boy: I'm not gonna assault you.

The little girl: Oh, it's not that at all.

The little boy: Then what?

The little girl: Well, my 23rd pair of chromosomes in every cell has two X chromosomes, and you have an X and a y. And the "y" is shrinking, so you won't have it anymore, and you will cease to exist. So why bother with men at all?

The little boy: Oh yeah, and who are you going to play with? Robots?

The little girl: Umm... yeah!