This image illustrates Tanner staging of puberty in girls. As for boys, it is more important to describe the changes seen as opposed to trying to link them to a particular stage. You should remember that Stage 1 is prepubertal and Stage 5 is post-pubertal
- For most girls (75%) the first sign is breast development (Thelarche), beginning on average at 9-10 years
- Breast development, the growth spurt and the development of the uterine lining are due to rising levels of oestrogens (from ovaries)
- Pubic & axillary hair growth is androgen dependent (from adrenal glands)
- The growth spurt occurs towards the start of puberty (average age 10.5 years)
- From start to finish puberty takes approximately 2.4 years (+/- 1.1 years)
Image by Michal Komorniczak, licensed under Creative Commons Attribution-Share Alike 3.0 Unported license.