Fertility chapter in book Yellow Emperor Classic Medicine written thousands year ago

Huang Di asked, "When one grows old, one cannot bear children. Is this due to heredity or to the loss of one's procreative energy?"
Qi Bo answered, "In general, the reproductive physiology of woman is such that at seven years of age her kidney energy becomes full, her permanent teeth come in, and her hair grows long. At fourteen years the tian kui, or fertility essence, matures, the ren/conception and chong/vital channels responsible for conception open, menstruation begins, and conception is possible. At twenty-one years the kidney energy is strong and healthy, the wisdom teeth appear, and the body is vital and flourishing. At twenty-eight years the bones and tendons are well developed and the hair and secondary sex characteristics are complete. This is the height of female development. At thirty-five years the yangming/stomach and large intestine channels that govern the major facial muscles begin to deplete, the muscles begin to atrophy, facial wrinkles appear, and the hair begins to thin. At forty-two all three yang channels—taiyang, shaoyang, and yangming—are exhausted, the entire face is wrinkled, and the hair begins to turn gray. At forty-nine years the ren and chong channels are completely empty, and the tien kui has dried up. Hence, the flow of the menses ceases and the woman is no longer able to conceive