Tanner scale

The scale defines physical measurements of development based on external primary and secondary sex characteristics, such as the size of the breasts, length of the penis, volume of the testes, and growth of pubic hair.

This scale was first quantified in 1969 by James Tanner, a British pediatrician, after a two-decade-long study following the physical changes in girls undergoing puberty.

[1][2][3][4] Due to natural variation, individuals pass through the Tanner stages at different rates, depending in particular on the timing of puberty.

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.

Males also stop growing and reach their adult height during Tanner V; usually this happens in their late teens at 16 to 17 years, [medical citation needed] but can be a lot later, even into the early 20s.