Okay, I call shenanigans on the databook's explanation for Hinata's well endowed bosom. I sincerely doubt that an official databook would call attention to a minor's melons. Hinata is only fifteen years old people! Wait until she's legal before you start drooling! By then, we may have another Tsunade in our hands.
Not to mention that Kakashi stated that you can't strengthen your internal organs through training. That's why the Gentle Fist is so effective, because there's no way to defend against it. Besides, with the databook's explanation, wouldn't Neji be getting swollen too?
I brainstorm with my multiple personalities.