The Tanner scale (also known as the Tanner stages) 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 by James Tanner, a British pediatrician, and thus bears his name.
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 treatment regimen to follow (adult, adolescent or pediatric).
Adapted from text by Lawrence Neinstein, M.D.
Tanner Itesticular volume less than 1.5 ml; small
penis of 3 cm or less (prepubertal) (typically age nine and younger)
Tanner IItesticular volume between 1.6 and 6 ml; skin on
scrotum thins, reddens and enlarges;
penis length unchanged (9–11)
Tanner IIItesticular volume between 6 and 12 ml; scrotum enlarges further;
penis begins to lengthen to about 6 cm (11–12.5)
Tanner IVtesticular volume between 12 and 20 ml; scrotum enlarges further and darkens; penis increases in length to 10 cm (12.5–14)
Tanner Vtesticular volume greater than 20 ml; adult scrotum and penis of 15 cm in length (14+)
Tanner Ino glandular tissue:
areola follows the skin contours of the chest (prepubertal) (typically age 10 and younger)
Tanner IIbreast bud forms, with small area of surrounding glandular tissue; areola begins to widen (10–11.5)
Tanner IIIbreast begins to become more elevated, and extends beyond the borders of the areola, which continues to widen but remains in contour with surrounding breast (11.5–13)
Tanner IVincreased breast size and elevation; areola and papilla form a secondary mound projecting from the contour of the surrounding breast (13–15)
Tanner Vbreast reaches final adult size; areola returns to contour of the surrounding breast, with a projecting central papilla. (15+)
Pubic hair (both male and female)
Tanner Ino pubic hair at all (prepubertal) (typically age 10 and younger)
Tanner IIsmall amount of long, downy hair with slight pigmentation at the base of the penis and scrotum (males) or on the
labia majora (females) (10–11.5)
Tanner IIIhair becomes more coarse and curly, and begins to extend laterally (11.5–13)
Tanner IVadult–like hair quality, extending across
pubis but sparing medial thighs (13–15)
Tanner Vhair extends to medial surface of the thighs (15+)
The scale has been criticized by the pornography industry for its potential to lead to false child pornography convictions, such as in the case when US federal authorities used it to assert that pornographic actress Lupe Fuentes was underage. Fuentes personally appeared at the trial and provided documentation that showed that the DVDs in question were legally produced. The author of the classification system himself has argued that age classification using the Tanner stages represents invalid use. Tanner stages do not match with chronological age, but rather maturity stages and thus are not diagnostic for age estimation.
