The female body is so much designed. Your groins are actually flat because nature let you protect your gonads internally. All humans have weak points, I guess, but there are none quite as fragile and immediately devastating, not to mention as hard to protect, as the balls.
How do girls feel about this? How did you first learn boys were weak there? How do you feel that any sized male will always have this sensitive weak spot that you don't ever have to worry about?