Tanner stage	Standard	Genitalia*	Pubic hair*	Growth	Other
1		Prepubertal Testes: < 2.5 cm (1.0 in)	Prepubertal, villus hair only	Basal: about 5.0 to 6.0 cm (2.0 to 2.4 in) per year	Adrenarche
2		Thinning and reddening of scrotum (11.9 years) Testes: 2.5 to 3.2 cm (1.0 to 1.28 in)	Sparse growth of slightly pigmented hair at base of penis (12.3 years)	Basal: about 5.0 to 6.0 cm (2.0 to 2.4 in) per year	Decrease in total body fat
3		Growth of penis, especially length (13.2 years) Testes: 3.3 to 4.0 cm (1.32 to 1.6 in)	Thicker, curlier hair spreads to the mons pubis (13.9 years)	Accelerated: about 7.0 to 8.0 cm (2.8 to 3.2 in) per year	Gynecomastia (13.2 years) Voice break (13.5 years) Muscle mass increase
4		Growth of penis and glands, darkening of scrotum (14.3 years) Testes: 4.1 to 4.5 cm (1.64 to 1.8 in)	Adult-type hair but no spread to medial thigh (14.7 years)	Peak velocity: about 10.0 cm (4.0 in) per year (13.8 years)	Axillary hair (14.0 years) Voice change (14.1 years) Acne (14.3 years)
5		Adult genitalia (15.1 years) Testes: > 4.5 cm (1.8 in)	Adult-type hair with spread to medial thighs but not up linea alba (15.3 years)	Deceleration and cessation (about 17 years)	Facial hair (14.9 years) Muscle mass continues to increase after Stage 5