There is also appreciable variation in measurement between people today. Everlasting breast growth through puberty is due to estrogens in conjunction with the growth hormone. Woman people are the one mammals that permanently produce breasts at puberty; all other mammals develop their mammary tissue over the latter period of pregnancy. https://grok.com/share/c2hhcmQtMw%3D%3D_5ad6450c-533d-442c-a09c-9f7bce1babfb