Snapshot A 6-year-old girl is brought to the pediatrician by her mother for a check-up. The girl complains that she has been teased by kids at her elementary school because she looks "older" than the other children. She has not yet experienced her first menstrual period. On physical examination, she has formed breast mounds (as seen in image) and scant pubic hair in her axillary and pubic regions. The pediatrician determines that the girl has signs of precocious puberty with Tanner stage 3 breast development and Tanner stage 2 pubic hair. Introduction Overview Tanner staging is performed to assess sexual development in girls and boys, from stage 1 (pre-adolescent) to stage 5 (adult) assigned independently to genitalia, pubic hair, and breasts ETIOLOGY Pathophysiology average age of puberty in girls is around 10.5 years average age of menarche among girls in US is 12.5 years average age of puberty in boys is around 11.5 years Associated conditions precocious puberty any sign of secondary sexual maturation in girls < 8 years of age or boys < 9 years of age delayed puberty no breast development or pubic hair in girls by age 13 no testicular enlargement in boys by age 14 constitutional growth delay most common cause of delayed puberty normal variant growth curve lags but is consistent children ultimately achieve target height potential pathological puberty delay rare may be due to systemic disease (i.e., IBD), malnutrition, gonadal dysgenesis, or endocrine abnormalities (i.e., hypothyroidism and hypopituitarism) CLASSIFICATION Tanner Stages of Sexual Development Stage Findings in Girls Findings in Boys Stage 1 No pubic hair Papillar elevation of the breasts No pubic hair No penile or testicular enlargement Stage 2 Pubic hair appears Breast bud forms Pubic hair appears Testicular enlargement Stage 3 Coarsening of pubic hair Breast enlarges and a mound forms Coarsening of pubic hair Penis size and length increases Stage 4 Coarse hair spreads across the pubis but still spares the thighs Breast enlarges to a mound on mound with a raised areola (ring of pigmented skin around the nipple) Coarse hair spreads across the pubis but still spares the thighs Penis width and glans increases in size Stage 5 Coarse hair spreads across the pubis and medial thigh Adult breast contour develops and the areola flattens Coarse hair spreads across the pubis and medial thigh Penis and testis enlarge to adult size