What age do boys go through puberty?

Oh so soon! Puberty consists of a cascade of events that occur over several years. Boys typically begin around 12 but starting as early as 9 and as late as 14 may be normal. Early clues include under arm odor and increase in size of the genitalia. Subsequent signs include growth spurts, voice changes, hair development, muscle growth, acne, and mood changes. For many, the changes start in the blink of an eye!