Pubertal changes in boys

The growth spurt in boys typically starts after the development of the genitals and pubic hair, so later in the sequence than it starts in girls. The maximum rate of growth is reached around 14 years old when males gain around 11½ to 12 cm per year. As in females the growth spurt spans around 2½ years from beginning to end. Enlargement of the testes and scrotum occurs during Tanner stage 2 and spermatogenesis commences towards the end of this stage, before the peak of the growth spurt. During stage 3 and 4 the scrotum and testes enlarge further and the texture of the scrotum changes. The penis starts to enlarge during stage 4.

Towards the end of the pubertal sequence, the increasing levels of hormones means the boy’s voice will deepen or break and he will start to develop both facial and underarm hair.