Folliculogenesis is the process of ovarian follicle development. In order to reach the ovulatory stage, an ovarian follicle will pass through the following stages: primordial (resting), primary, secondary (pre-antral), tertiary (antral), and, finally, the pre-ovulatory (Graafian) follicle stage. According to dogma in the field, in females, the peak number of ovarian follicles occurs in the fetus at mid-gestation and is approximately seven million. This number then declines to two million at birth, half a million at puberty, 25 thousand at the age of 37 years, and less than one thousand at menopause. This progressive decline in follicle count with age is due to a natural breakdown process called follicular atresia that affects 99.9% of all follicles.