the predator physiology is based off that of a human - it might have different skin colors or texture, and a different head, but from the neck down, it is almost identical to a human - even the same number of fingers and same proportions. no other creature on our earth (or that we can refer to) exhibits the same kind of bipedal nature, muscle structure, and proportions. i think its a pretty good arguement that the male predator doesn't have nipples, so the females wouldn't have boobs, but what anatomical neccessity do human males possess nipples for anyway?
i think we're overlooking one simple fact - the predator body, sans the head, is more closely related to human physiology at its core, than any other animal we can think of. i say "let them have their predators, and their boobs, too".