When a boy hits the stage of puberty, he may notice a change in the size of his penis. This is because of the increasing levels of testosterone in the body. It is during this time that the penis growth will be rapid and at its peak. It is likely to increase in length and girth. The penis growth is said to end when the stage of puberty ends. For most boys, the growth of the penis stops in their late teen years.
That said, during this stage, teens are often concerned about their penis size. And because they're embarrassed to question others about their penis size, they're almost always wondering what's normal. This could therefore go from being a source of curiosity to that of anxiety, which must be prevented.
Young boys must be told that penis sizes have no association whatsoever with medical problems. It is determined by one's genes and most importantly, there's a huge difference between how one's penis looks when it is relaxed and when it is going through an erection.