Puberty is the time of life when people develop physically and sexually so that they can have children. It is the time when male and female sex characteristics appear and when changes in the sexual organs occur.
Puberty is the entire process of changes affecting the body and its hormones that accompany sexual maturation. In general, puberty usually starts for girls between the ages of 9 and 11, and for most boys between the ages of 9½ and 13, although the exact age at which puberty starts varies widely among individuals.
WebMD Medical Reference from Healthwise