Puberty: Timing, Signs & What to Expect

Puberty usually begins between the ages of 8 and 13 for girls, and between the ages of 10 and 15 for boys. Signs of puberty include changes in body shape and size, as well as the development of secondary sexual characteristics, such as breasts in girls and facial hair in boys. Puberty is triggered by a hormonal signal from the brain, and is influenced by both genetic and environmental factors.