CorpusHuman Anatomy
ReproductivePhysiological process

Puberty

Also known as: adolescence, menarche, thelarche, spermarche, Tanner stages, adrenarche

The transition to reproductive maturity, triggered by reactivation of pulsatile GnRH secretion, during which secondary sexual characteristics develop, a growth spurt occurs and gametogenesis begins.

Overview

Girls — first signThelarche ≈10–11 years
Menarche≈12–13 years
Boys — first signTesticular volume ≥4 mL at ≈11–12 years

The GnRH pulse generator is active in fetal life and in the first months after birth ("mini-puberty"), then is restrained throughout childhood. Puberty begins when kisspeptin-driven GnRH pulses resume, initially during sleep, raising LH and FSH and then gonadal sex steroids. Timing is mainly genetic but also depends on adequate nutrition and body fat (leptin) and is influenced by environment. Adrenarche (rising adrenal androgens at ≈6–8 years) is a separate process that contributes pubic and axillary hair, body odour and acne.

Girls: the first sign is usually thelarche (breast budding) at ≈10–11 years (range ≈8–13), followed by pubic hair and the growth spurt (peak height velocity early, ≈12 years) and menarche ≈2–2.5 years after thelarche (≈12–13 years); early cycles are often anovulatory. Boys: the first sign is testicular enlargement to ≥4 mL at ≈11–12 years (range ≈9–14), followed by penile growth, pubic hair, voice change, spermarche (≈13–14 years) and a later, larger growth spurt (peak ≈14 years). Development is staged with the Tanner (sexual maturity) stages 1–5 for breasts/genitalia and pubic hair. Estrogen in both sexes ultimately closes the epiphyses, ending linear growth.

Location

Whole body; initiated in the hypothalamus.

Function

  • Attainment of fertility (ovulation, spermatogenesis).
  • Development of secondary sexual characteristics.
  • Pubertal growth spurt and attainment of adult height and bone mass.

Clinical significance

Precocious puberty

Onset before 8 years in girls or 9 years in boys. Central (GnRH-dependent): usually idiopathic in girls, but often due to CNS lesions (hypothalamic hamartoma, tumours) in boys — treated with GnRH agonists. Peripheral (GnRH-independent): congenital adrenal hyperplasia, McCune–Albright syndrome, gonadal or adrenal tumours, hCG-secreting tumours, exogenous steroids.

Delayed puberty

No breast development by 13 in girls or no testicular enlargement by 14 in boys. Commonest cause is constitutional delay (especially boys; delayed bone age, family history). Others: hypogonadotropic (chronic illness, low weight, Kallmann syndrome, pituitary disease) or hypergonadotropic (Turner, Klinefelter, gonadal damage).

Compiled from standard anatomy and physiology references — see the Reproductive System sources. For education only; not medical advice.