The Tanner scale (also known as the Tanner stages or Sexual Maturity Rating (SMR)) 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

breast The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues. In females, it serves as the mammary gland, which produces and sec ...

s, 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 Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a ...

. Among researchers who study puberty, the Tanner scale is commonly considered the "gold standard" for assessing pubertal status when it is conducted by a trained medical examiner. In HIV treatment, the Tanner scale is used to determine which regimen to follow for pediatric or adolescent patients on antiretroviral therapy (adult, adolescent, or pediatric guidelines). The Tanner scale has also been used in forensics to determine aging, but its usage has decreased due to lack of reliability.

Stages

Adapted from ''Adolescent Health Care: a practical guide'' by Lawrence Neinstein, M.D.

Genitals (male)

; Tanner I : testicular volume less than 1.5 ml; small

penis A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males d ...

( prepubertal) ; Tanner II : testicular volume between 1.6 and 6 ml; skin on scrotum thins, reddens and enlarges; penis length unchanged ; Tanner III : testicular volume between 6 and 12 ml; scrotum enlarges further; penis begins to lengthen ; Tanner IV : testicular volume between 12 and 20 ml; scrotum enlarges further and darkens; penis increases in length ; Tanner V : testicular volume greater than 20 ml; adult scrotum and penis Male genitalia five Tanner stages

Breasts (female)

; Tanner I : no glandular tissue:

areola The human areola (''areola mammae'', or ) is the pigmented area on the breast around the nipple. Areola, more generally, is a small circular area on the body with a different histology from the surrounding tissue, or other small circular ...

follows the skin contours of the chest ( prepubertal) ; Tanner II :

breast bud Thelarche, also known as breast budding, is the onset of secondary breast development, often representing the beginning of pubertal development. It is the stage at which male and female breasts differentiate due to variance in hormone levels; howe ...

forms, with small area of surrounding glandular tissue; areola begins to widen ; Tanner III : breast begins to become more elevated, and extends beyond the borders of the areola, which continues to widen but remains in contour with surrounding breast ; Tanner IV : increased breast sizing and elevation; areola and papilla form a secondary mound projecting from the contour of the surrounding breast ; Tanner V : breast reaches final adult size; areola returns to contour of the surrounding breast, with a projecting central papilla

Pubic hair (both male and female)

; Tanner I : no pubic hair at all ( prepubertal) ; Tanner II : small amount of long, downy hair with slight pigmentation at the base of the

and

scrotum The scrotum or scrotal sac is an anatomical male reproductive structure located at the base of the penis that consists of a suspended dual-chambered sac of skin and smooth muscle. It is present in most terrestrial male mammals. The scrotum co ...

(males) or on the

labia majora The labia majora (singular: ''labium majus'') are two prominent longitudinal cutaneous folds that extend downward and backward from the mons pubis to the perineum. Together with the labia minora they form the labia of the vulva. The labia maj ...

(females) ; Tanner III : hair becomes more coarse and curly, and begins to extend laterally ; Tanner IV : adult-like hair quality, extending across pubis but sparing medial thighs ; Tanner V : hair extends to medial surface of the thighs

Height

During Tanner V, females stop growing and reach their adult height. Usually, this happens in their mid teens at 14 or 15 years for females. Males also stop growing and reach their adult height during Tanner V; usually this happens in their late teens at 16-17 years.

Tanner Stage data in history

In 1970, white boys reached the last Tanner stage, the postpubertal stage, on average at the age of 14.9 years and girls around the age of 14 depending on social class and the particular study. In the nearly fifty years since those studies, the ages at which children are beginning puberty has only declined: "The age of puberty, especially female puberty, has been decreasing in western cultures for decades now ... for example, at the turn of the 20th century, the average age for an American girl to get her period was 16 or 17. Today, that number has decreased to 12 or 13 years."

Criticism

The scale has been criticized by the pornography industry for its potential to lead to false

child pornography Child pornography (also called CP, child sexual abuse material, CSAM, child porn, or kiddie porn) is pornography that unlawfully exploits children for sexual stimulation. It may be produced with the direct involvement or sexual assault of a ...

convictions, such as in the case of pornographic actress Lupe Fuentes where United States federal authorities used it to assert that she was not an adult despite her age. Fuentes personally appeared at the trial and provided documentation that showed that the DVDs in question were legally produced. Tanner, the author of the classification system, has argued that age classification using the stages of the scale misrepresents the intended use. Tanner stages do not match with chronological age, but rather maturity stages and thus are not diagnostic for age estimation.

References

External links

The Male Tanner stages

* * {{Authority control Medical scales Endocrinology Paraphilias Pediatrics Sexology Sexuality and age Puberty 1969 introductions