page_title: Tanner scale
section_title: Genitals (male)
hierarchical_section_title: Tanner scale / Definitions of stages / Genitals (male)
caption_attribution_description: Français&#160;: Cinq étapes de la Classification de Tanner - développement de l'appareil génital masculin English: Development of an uncircumcised human penis (five Tanner stages).
context_page_description: The Tanner scale is a scale of physical development in children, adolescents and adults. The scale defines physical measurements of development based on external primary and secondary sex characteristics, such as the size of the breasts, genitals, testicular volume and development of pubic hair. This scale was first identified in 1969 by James Tanner, a British pediatrician, after a two-decade-long study following the physical changes in girls undergoing puberty.
  Due to natural variation, individuals pass through the Tanner stages at different rates, depending in particular on the timing of puberty. In HIV treatment, the Tanner scale is used to determine which regimen to follow for pediatric or adolescent patients on antiretroviral therapy. The Tanner scale has also been used in forensics to determine aging, but its usage has decreased due to lack of reliability.
context_section_description: Tanner I
  testicular volume less than 1.5 ml; small penis (prepubertal; typically age nine and younger)
  Tanner II
  testicular volume between 1.6 and 6 ml; skin on scrotum thins, reddens and enlarges; penis length unchanged (9–11)
  Tanner III
  testicular volume between 6 and 12 ml; scrotum enlarges further; penis begins to lengthen (11–12.5)
  Tanner IV
  testicular volume between 12 and 20 ml; scrotum enlarges further and darkens; penis increases in length (12.5–14)
  Tanner V
  testicular volume greater than 20 ml; adult scrotum and penis (14+)
caption: Photos of the Tanner scale for males.
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