| | Family Health | Teen Health
Puberty Onset: Physical Signs & Typical Timing
Puberty begins when the hypothalamic‑pituitary‑gonadal axis activates. Timing varies widely (genetics, nutrition, health, environment).
Typical Age Ranges
- Girls: Breast bud (thelarche) 8–13 yr (avg 10); menarche 10–15 yr (avg 12.5).
- Boys: Testicular enlargement (>4 mL) 9–14 yr (avg 11.5); peak height velocity 13–14 yr.
Tanner Stages (Sexual Maturity Rating)
- Stage 1: Prepubertal.
- Stage 2: Onset (breast buds / testicular growth).
- Stage 3: Acceleration (pubic hair, growth spurt).
- Stage 4: Deceleration (menarche in girls; voice deepening in boys).
- Stage 5: Adult.
Key Signs by Sex
| Girls | Boys |
|---|---|
| Thelarche (breast buds) | Testicular enlargement (>4 mL) |
| Pubarche (pubic hair) | Pubarche (pubic hair) |
| Growth spurt (peaks before menarche) | Penis growth, scrotal thinning |
| Menarche | Spermarche (nocturnal emissions) |
| Axillary hair | Axillary hair, facial hair |
| Acne, body odor | Acne, body odor, voice deepening |