The Yellow Emperors Classic of Internal Medicine is a classical Chinese Medicine textbook, and one of the first to document the cycles of evolution for males and females.
Here is a summary of the cycles:-
7 Years female cycle
A Woman’s kidney becomes abundant, teeth change and hair grows strong
The Kidney function in Chinese medicine is more than just filtration and excretion of fluids. The Kidney’s are where the life force potential is stored. The Chinese called this potential the Jing. Jing is partially inherited from our parents, and partially created through the conversion of food, water and air.
Jing is also responsible for governing the growth and development of the human being, for developing secondary sexual characteristics, and for reproduction.
At 7 years of age, Kidney energy in a woman becomes abundant, and it is then manifested as strong teeth, and good quality hair growth.
14 Year female cycle
Her menstruation appears as the Ren meridian (the sea of Yin) flows and the Qi and blood in the Chong meridian (the sea of blood) becomes abundant, she can have children.
As a child matures, the conception meridian starts to fill with Qi , and the Chong meridian starts to fill with blood and Blood. When it is full, menstruation starts.
Both of these meridians run along the anterior of the body and run through the central line of the torso through the uterus.
It is interesting to note the relatively late age of menarche considered normal, as most women have their first period much earlier. We can adjust the timing somewhat as the Chinese would have been using the Lunar calendar, as opposed to the Gregorian calendar. By doing this, it would bring it back to about 13 Gregorian years.
21 Year Female
At 21, the level of kidney qi attains its peak and her body’s development stops and her wisdom teeth have developed.
The female for is fully developed, and now we can direct the energies from growth towards other endeavours.
28 Year Female
Vital energy and blood are abundant, her bones and muscles are strong, her hair grows to full length and her body is in optimal condition.
Like a plant that has fully grown and gone into blossom, this is the manifestation of optimum expression of your physical being. It is considered an idea time to have children.
35 Year Female
Her peak condition declines gradually. Her energy in the yang ming meridian declines. Her face starts to wither and her hair starts to fall out.
This is a pretty harsh summary of 35 year old women. A woman in good health can still be highly fertile. It merely states that the physical has reached its fullest potential, and now it is time to cultivate other attributes.
42 Year Female
At 42, the three yang meridians in the upper body begin to decline, which leads to facial sagging, and graying hair which eventually turns white.
At this age, it is generally more difficult for a woman to fall pregnant. Fertility becomes harder, but still possible.
49 Year Female
The Ren meridian (Conception Vessel) and Chong meridian vital energy declines, her menstruation dries up, her physique turns old and feeble and she is no longer able to conceive
As our menses stop, the focus goes away from reproduction. This is not seen as a negative in Chinese Medicine, but rather a liberation, and a freeing of your life force to pursue other things. Older men and women are considered freed from the duties of family and society, and can direct their energies inwards towards understanding and honouring themselves, and then mirror that back out to society.