#2 Technically, you might’ve *always* had hair in that area
It was just a different type of hair, called vellus hair, which is the the barely detectable peach fuzz that covers most of your body. See, during puberty, the body amps up its levels of androgens, a group of hormones that includes testosterone. At the same time, vellus hair follicles in the crotch area become sensitive to those androgens. What do you get when you combine those two conditions? You guessed it: Darker, thicker hair below the belt.