Puberty
Not long after a boy's testicles and penis start to grow, pubic hair (, ) begins to appear. Pubic hair is hair that grows in the pubic region, which is the part of the body where the penis is. Pubic hair is shorter, curlier, and rougher than hair on the head. It usually starts growing on the abdomen above the penis at the place where it joins the body. (The abdomen is the part of the torso where the navel or bellybutton is.) There may also be some hair on the scrotum. After about six months to a year, there will be a large triangle of hair in the pubic region. Within three to four years after puberty begins, there is a lot of pubic hair in the area above the penis. Later on, pubic hair also grows on the abdomen upwards towards the navel and on the insides of the thighs.