Physiology Tanner Stages - Boys		Tanner stages for pubic hair in boys are shown in the graphic on this page, but again actual photos with more detailed descriptions are also available. The Tanner stages in boys start with stage 1, which is prepubertal. In this stage, there are relatively small testes and no pubic hair. As the boy goes through puberty, you can see that the testes continue to grow. Growth of the penis also proceeds, both in length and width. Development of pubic hair begins along the base of the penis. As puberty progresses, the hair becomes darker, more coarse and more abundant, eventually spreading to the thighs. Return to top of page