Normal sexual development in girls, as outlined by the Tanner Stages in girls, differs from developmental development in boys in two significant ways. First sexual development in girls on average begins and finishes at a younger chronologic age. Second peak linear growth comes at an earlier stage in development, making it common for girls to be taller than boys of the same age early in puberty.
In girls the ovaries are not visible, unlike the testes in boys, and so the Tanner stages are defined in terms of breast development and pubic hair growth.
Height increases, as measured by peak growth rates, tend to occur at an earlier Tanner stage in girls than analogous Tanner Stages in boys. The maximum peak growth in girls typically happens during the Tanner 2 timeframe, with an average age of peak growth being about 11 ½, although this ages as in boys varies greatly
|Pubic Hair||Breast Development|
|Tanner Stage 1||Prepubertal, no pubic hair at all||No gland tissue, areola flat to the chest wall (typically until about age 10)|
|Tanner Stage 2||Small amounts of fine hair on labia majora (typically age 10-
|Breast bud and small amount of gland tissue, areola widens slightly (age 8 ¾-12 ¾)|
|Tanner Stage 3||Hair gets more coarse and/or curly, grows more laterally (age
9 ½ – 14)
|Breast grows, glandular tissue extends outside the areola, but areola still in contour of breast (age 9 ¾- 13 ¾)|
|Tanner Stage 4||Adult hair quality, adult distribution except spares medial thighs (age 10 ½ – 15 ¼)||Breast grows and papilla develop causing areola to project from the breast contour (age 10 ½ – 15 ¼)|
|Tanner Stage 5||Hair extends onto medial thighs||Breast grows to adult size, areola returns to contour of the rest of the breast with central papilla projecting|