Male Tanner Stage

1. Stage: Tanner 1 (Prepubertal)
   1. Height increases at basal rate: 5-6 cm/year
   2. Testes
      1. Smaller than 4 ml or long axis <2.5 cm
   3. Pubic Hair
      1. No coarse, pigmented hair
   4. Penis Stage
      1. No growth
2. Stage: Tanner 2
   1. Height increases at basal rate: 5-6 cm/year
   2. Testes
      1. Size 4 ml or long axis 2.5 to 3.2 cm
      2. Age 11.5 years (age 9.5 to 13.5 years)
   3. Pubic Hair
      1. Minimal coarse, pigmented hair at base of penis
      2. Age 12.0 years (age 9.9 to 14.0 years)
   4. Penis Stage
      1. Earliest increased length and width
      2. Age 11.5 years (age 10.5-14.5 years)
3. Stage: Tanner 3
   1. Height increases at accelerated rate: 7-8 cm/year
   2. Testes
      1. Size 12 ml or long axis 3.6 cm
      2. Age 14.0 years (11.5-16.5 years)
   3. Pubic Hair
      1. Coarse, dark curly hair spread over the pubis
      2. Age 13.1 years (11.2-15.0 years)
   4. Penis Stage
      1. Increased length and width
      2. Age 12.4 years (10.1-14.6 years)
   5. Other Changes
      1. Gynecomastia may occur (age 13.2 years)
      2. Voice breaks (age 13.5 years)
      3. Muscle mass increases
4. Stage: Tanner 4
   1. Height increases at peak rate: 10 cm/year (age 13.8)
   2. Pubic Hair
      1. Hair of adult quality
      2. Not spread to junction of medial thigh with perineum
      3. Age 13.9 years (12.0-15.8 years)
   3. Penis
      1. Continued growth in length and width
      2. Age 13.2 years (11.2-15.3 years)
   4. Testes
      1. Length 4.1 to 4.5 cm
   5. Other Changes
      1. Axillary hair (age 14.0 years)
      2. Voice changes (age 14.1 years)
      3. Acne Vulgaris (age 14.3 years)
5. Stage: Tanner 5
   1. No further height increases after age 17 years
   2. Pubic Hair
      1. Adult pubic hair distribution (15.3 years)
      2. Pubic hair spreads to medial thigh
      3. No hair spread to linea alba
   3. Penis
      1. Mature genital size by 16.5 years
   4. Testes
      1. Length >4.5 cm
   5. Secondary sexual characteristics
      1. Facial hair present on sides
      2. Mature male physique
      3. Gynecomastia disappears
6. Exam: Testicle Size (typical ranges)
   1. Birth to 6 months
      1. Size: 1.5 cm long and 1.0 cm wide
   2. Child <6 years
      1. Size 2 cm long and 1.2 cm wide
   3. Adult:
      1. Size 4-5 cm long and 3.0 cm wide and 3.0 cm deep (AP)
      2. Testicle length <3.5 cm is considered small for an adult
7. Exam: Growth in Boys
   1. Peak height velocity: Age 13.5 (11.7-15.3 years)
   2. Basal growth occurs up until Tanner Stage 3
      1. Basal Growth rate: 5.0 to 6.0 cm per year
   3. Pubertal Growth
      1. Boys who mature average time: 9.5 (7.1-11.9) cm/yr
      2. Boys who mature early: 10.3 (7.9-12.5) cm/yr
      3. Boys who mature late: 8.5 (6.3-10.7) cm/yr
8. Reference
   1. Tanner (1966) Growth at Adolescence, Appleton
   2. Marshall (1970) Arch Dis Child 45:13-23
   3. Tanner (1985) J Pediatr 107(3):317