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Sexual maturity rating

In 1962, James Tanner published a Sexual Maturity Rating system. The scale ranges from prepubertal (stage I) to adult (stage V).

For girls, the stages of puberty are based on breast size (B) and shape, and pubic hair (P) development and distribution. For boys, the stages of puberty are based on the genitalia (G) (size and shape of the penis and scrotum) and on pubic hair (P) development and distribution.

Females: Breast development

The onset of breast development in females is called thelarche.

Note B= breast, not 'boy'

  • Stage I (B1) - prepubertal; flat appearance with only the papilla (nipple) raised.
  • Stage II (B2) - the breast bud is present so that the areola protrudes.
  • Stage III (B3) - the breast tissue extends past the areola causing the elevation of the breast along with the areola. The contour of the areola is the same as the rest of the breast.
  • Stage IV (B4) - areola forms a separate contour from the rest of the breast creating what is referred to as the "mound on the mound" appearance.
  • Stage V (B5) - adult; the areola flattens down assuming the contour of the rest of the breast.

Males: Testes and scrotum development

Staging of male genital development is based primarily on changes in the appearance of the penis and scrotum and not on testicular size, because testicular size varies widely between individuals. In other words, one boy's stage III testes may be the size of another's stage V testes.

Note G= genitalia, not 'girl'

  • Stage I (G1) - prepubertal appearance; the testes are less than or equal to 1.5 cc in volume.
  • Stage II (G2) - the scrotum becomes pendulous with the skin becoming thinner. Testicular volume is from 1.6 to 6cc.
  • Stage III (G3) - the scrotum coarsens and the testes are 6 to 12 cc. The penis lengthens.
  • Stage VI (G4) - the penis grows in length and circumference and the testes are from 12-20cc.
  • Stage V (G5) - adult appearance of penis with testes that are usually greater than or equal to 20cc in volume.

Females and Males: pubic hair development

Pubarche refers to the onset of pubic hair growth. The term adrenarche is broader, indicating the increased production of androgens by the adrenal glands. Signs of adrenarche include pubic hair growth as well as other secondary sexual hair (e.g., axillary and facial) and acne. Pubic hair rating is similar for both males and females.

  • Stage I (P1) - prepubertal, lanugo may be present in genital area but it is fine and downy.
  • Stage II (P2) - sparse growth of pubic hair in the midline, mainly at the base of the penis or along the labia majora.
  • Stage III (P3) - more hair grows so that it is visible from several feet, along with coarsening and increased pigmentation in some people.
  • Stage IV (P4) - hair now makes a triangle over the pubis
  • Stage V (P5) - adult; hair is outside of triangle, extending up the abdomen and down the thighs.

Eighty percent of females begin with breast development (thelarche) and the other 20% with pubarche. The most common sequence of events is as follows:

  • P2 > B2 > Peak Height Velocity > B3 > P3 > P4 > B4 > Menarche > P5 > B5

Ninety-eight percent of males begin with enlargement of the testes. This makes sense because the testes are where most of the androgens come from. The most common sequence for males is as follows:

  • G2 > G3 > P2 > G4 > P3 > Peak Height Velocity > P4 > G5 > P5

More info: breast development from Queen Mary University of London

More info: female genital development from afraidtoask.com

More info: male genitalia development from afraidtoask.com