Tanner described several stages through which a boy passes as he progresses from childhood to becoming an adult. Changes to the pubic hair and genitalia are the primary morphologic findings, with additional changes to skin, mood, muscle development and other areas.
|
Changes to Pubic Hair |
Tanner Stage |
|
vellus (short, fine hairs) of the pubis resembles that over the abdomen |
Stage I |
|
sparse growth of long, slightly pigmented, downy hair; straight or only slightly curled; appears chiefly around the base of the penis |
Stage II |
|
hair is considerably darker, coarser and more curled; the hair spreads laterally sparsely over the junction of the pubis |
Stage III |
|
hair more adult-like and is coarse and curly; the area covered is still considerably smaller than most adults; there is no spread to the medial surface of the thighs |
Stage IV |
|
hair is abundant adult-like in quality and type; the hair extends to involve the medial surface of the thighs |
Stage V |
|
Changes to Genitalia |
Tanner Stage |
|
the testes, scrotum and penis are about the same size and proportion as in early childhood |
Stage I |
|
scrotum and testes enlarge; the scrotal sac reddens and changes in texture; there is little or to no enlargement of the penis |
Stage II |
|
there is further growth of the testes and scrotum; the penis begins to enlarge, mostly in length |
Stage III |
|
the testes and scrotum continue to enlarge; scrotal skin continues to darken; penis continues to grow in breadth and length with development of the glans |
Stage IV |
|
the genitals are of adult size and shape, with no further enlargement |
Stage V |
|
Stage |
Early |
Median |
Late |
|
penis, Stage II |
9.2 |
10.5 |
13.7 |
|
pubic hair, Stage II |
9.9 |
12.0 |
14.1 |
|
penis, Stage III |
10.1 |
12.4 |
14.6 |
|
pubic hair, Stage III |
11.2 |
13.1 |
14.9 |
|
penis, Stage IV |
11.2 |
13.2 |
15.4 |
|
pubic hair, Stage IV |
12.0 |
13.9 |
15.7 |
from Figure 3, Tanner (1985) and Table 15-4, Behrman et al (1996)
Precocious puberty:
• Classically this is any sign of secondary sexual maturation before 9 years of age.
• Herman-Giddens et al found that almost a third of Black, Hispanic and White boys had penile Stage II changes when 8 years of age (although pubic hair growth was seen in only 5% of blacks, 2.7% Hispanics and 0% Whites).
Mean Age for Stage Transition from the National Health and Nutrition Examination
|
Stage |
White |
Blacks |
Hispanic |
|
pubic hair, Stage II |
12.0 |
11.2 |
12.3 |
|
pubic hair, Stage III |
12.6 |
12.5 |
13.1 |
|
pubic hair, Stage IV |
13.5 |
13.7 |
14.1 |
|
pubic hair, Stage V |
15.7 |
15.4 |
15.8 |
|
penis, Stage II |
10.1 |
9.5 |
10.4 |
|
penis, Stage III |
12.4 |
11.8 |
12.5 |
|
penis, Stage IV |
13.5 |
13.4 |
13.7 |
|
penis, Stage V |
15.9 |
14.9 |
15.7 |
from Table 2, Herman-Giddens et al (page 1026)
Delayed puberty: Absence of Stage II development at age 15 years.
Specialty: Pedatrics, Obstetrics & Gynecology, Urology
