Growth spurts hit their peak approximately two years after puberty begins. Puberty generally begins between the ages of 8 and 13 for girls or 10 and 13 for boys. The growth spurt for girls usually happens between 10 and 14, with boys' occurring later.
A teenager's body experiences many changes during puberty. It is a time of sexual maturation in which hormones play a major role. Girls' bodies begin to prepare for childbearing, with breasts getting larger and hips becoming more rounded. They begin menstruating during this time. Boys' testicles begin to produce sperm and their voices deepen. Both sexes begin to develop pubic hair.