Oogenesis is the production of eggs, begins in the fetus. Oogonia, the diploid stem cells of female gametes, are converted to primary oocytes before birth.
Each month, one primary oocyte completes meiosis I, producing a large secondary oocyte. Meiosis II of the secondary oocyte produces a functional ovum, but does not occur in humans unless a sperm penetrates the secondary oocyte.
The ovarian cycle has Two phases: Follicular phase and Luteal phase