Only 400-500 follicles typically develop and ovulate during a woman’s lifetime, which is only about 0.1% of the total. During the initial period of embryonic development, there are about 600,000 oogenic cells, which later on during development, these cells are continuously occluded and only 2 million remain by the time of birth. Multiple follicles degenerate again during childhood, and only about 300,000 remain at the onset of puberty. After the first menstruation, each month with the onset of menstruation, a batch of follicles develops, usually 11-13 at a time. This batch of follicles undergoes developmental selection, of which generally only one dominant follicle reaches full maturity and expels an egg, while the rest of the follicles develop to a certain point and die on their own.