DefinitionPuberty is the time during which sexual and physical characteristics mature. Precocious puberty is when these body changes happen earlier than normal.Alternative NamesPubertas praecoxCauses, incidence, and risk factorsPuberty usually begins between ages 10 and 14 for girls, and ages 12 and 16 for boys. Some African American girls may start puberty earlier, around age 9.The exact age a child enters puberty depends on a number of factors, including family history, nutrition, and gender.Often there is no clear cause for precocious puberty, but some cases are due to changes in the brain, genetic problems, or certain tumors that release hormones. These conditions include:Congenital adrenal hyperplasiaDisorders of the testicles, ovaries, or adrenal glandsHypothalamic hamartomaMcCune-Al