Seriously my favourite Blonde joke of all time:

A redhead, a brunette and a blonde are in the waiting room at the doctor's office. All 3 of them are expectant mothers and are just there to see how the babies are doing. All except the blonde have had an ultrasound. They've just struck up a conversation.

Redhead: It's weird you know - my husband and I conceived this baby with me in the submissive position. Turns out we're having a girl. I wonder if there's anything to that?

Brunette: Seriously? That's unreal. I was in the dominant position and sure enough - we're having a boy. Just found out last week.

The blonde starts to sob.

Brunette and Redhead: What's wrong?

Blonde: [sob] I'm gonna have puppies!