Normal Adolescent Growth, Development, and Psychosocial Milestones
Puberty and growth
Puberty is a staged process best described with Tanner staging of breast development, pubic hair, genital development, and menarche. In girls, breast budding typically begins between ages 8 and 13; menarche follows thelarche by about 2–2.5 years. In boys, testicular enlargement (at least 4 mL or more than 2.5 cm long) is usually the first sign, beginning between ages 9 and 14; penile growth and voice change occur later. The pubertal growth spurt peaks around Tanner stage 3 in girls and stage 4 in boys, and boys grow for longer. Bone age helps distinguish constitutional delay from pathologic delay, but treatment decisions require history, examination, and sometimes laboratory testing.
Psychosocial development
Cognitive development moves from concrete to formal operational thinking, but decision-making continues developing into the mid-20s because prefrontal control matures later than reward circuitry. Erikson's identity-versus-role-confusion stage predicts experimentation with roles, values, and peers. Peer influence peaks in early to mid-adolescence; parent conflict often increases while attachment remains important. Sleep phase delay is physiologic, not laziness.
Traps
Questions often mislabel normal variation as pathology. Gynecomastia is common in mid-puberty and usually resolves. Asymmetric breast or testicular growth can be normal. Do not diagnose delayed puberty in a 13-year-old girl with no breast development without considering family history and bone age. Precocious puberty is breast development before age 8 in girls or testicular enlargement before age 9 in boys.
Rule of thumb
Evaluate delayed puberty if a girl has no breast development by age 13 or no menarche by age 16, or a boy has no testicular enlargement by age 14. In a 14-year-old boy with short stature and no pubic hair, obtain bone age and consider constitutional delay versus hypogonadism.