Stage 1: Pre-adolescent
GENITAL STAGE
Testes, scrotum, and penis are about the same size and proportion as those in early childhood.
PUBIC HAIR STAGE
Vellus over the pubes is no further developed than that over the abdominal wall, i.e., no pubic hair.
Stage 2
GENITAL STAGE
Scrotum and testes have enlarged, and there is a change in the texture of scrotal skin and some reddening of scrotal skin.
PUBIC HAIR STAGE
There is sparse growth of long, slightly pigmented, downy hair, straight or only slightly curled, appearing chiefly at base of penis.
Stage 3
GENITAL STAGE
Growth of the penis has occurred, at first mainly in length but with some increase in breadth. There has been further growth of the testes and the scrotum.
PUBIC HAIR STAGE
Hair is considerably darker, coarser, and more curled and spreads sparsely over junction of pubes.
Stage 4
GENITAL STAGE
The penis is further enlarged in length and breadth, with development of glans. The testes and the scrotum are further enlarged. There is also further darkening of scrotal skin.
PUBIC HAIR STAGE
Hair is now adult in type, but the area covered by it is smaller than that in most adults. There is no spread to the medial surface of the thighs.
Stage 5: Adult
GENITAL STAGE
Genitalia are adult in size and shape. No further enlargement takes place after stage 5 is reached.
PUBIC HAIR STAGE
Hair is adult in quantity and type, distributed as an inverse triangle. There is spread to the medial surface of the thighs but not up the linea alba or elsewhere above the base of the inverse triangle.
