Sequence of events by which a child becomes a young adult, characterized by the beginning of gonadotropin secretion, gametogenesis, secretion of gonadal hormones, development of secondary sexual characteristics and reproductive functions; sexual dimorphism is accentuated. In girls, the first signs of normal puberty may be evident after age 8 with the process largely completed by age 16; in boys, normal puberty commonly begins at age 9 and is largely completed by age 18. Ethnic and geographic factors may influence the time at which various events typical of puberty occur.