[quote=@GreivousKhan]
<Snipped quote by ImportantNobody>

You obviously don't have breast. You have any idea how sensitive those can be? 

Don't answer that.

Anyway, in terms of actual damage would depend allot on cup size and if the person is using their bare hands/knuckles (along with where on the breast they struck.) 

Edit: also, groin shots to females, depending on where/how they hit...can hurt allot too... not as much as a male probably but food for thought. 
[/quote]

I'm not sure just being sensitive would cause the attack to be effective. If you were just going about your daily life and got hit then the sensitivity would be a pain (pun intended), but if you're in a battle, how much would one truly care? I guess it would be up to the roleplayer being attacked if they decide sensitivity plays an issue, or in a story where you could come up with the plot, but it just doesn't seem believable to me that a character would get hit in the breasts and be taken out of the fight.

I know groin shots would hurt either way, but would it be worse than getting hit anywhere else?

Guys getting hit in the groin is still done mostly for laughs, but does happen a few rare times in a serious manner. Probably not exploited as much as it could.