“If I have to stare at a backside for hours on end it may as well be a girl, right?”
Joking aside, I think the question is “why not”. In your case particularly, half and half sounds like a fair and faithful representation. I haven’t thought about it much, but my answer would probably espouse something along the lines of “variety and freedom”.
Edit: Okay. When I first heard this, bottoms weren’t really a thing. My bad.