To prove all my bloody colleagues wrong? 
I'm 7 months pg and we don't want to know the sex of the baby. Every colleague who asks, "Is it a boy or a girl?" responds to my "We'll find out on the day," with, "OK, but it's a boy of course".
Yes, my bump is all at the front, but maybe, just maybe, that's how I'm built and nothing to do with whether my baby had a penis or vagina. Not that I care either way but I don't want my unborn child to reinforce all their lazy stereotypes.
I'm probably BU, but as I'm 7 months gone you can disagree with me at your peril 