The ovaries of a normal mature woman ovulate cyclically and eggs are a basic requirement for a woman to be fertile. Eggs are developed from follicles, of which there are about 2,000,000 during fetal life, most of which subsequently degenerate, leaving only 300,000 at puberty. When a woman enters her reproductive years, she will have a group of follicles each month, which will develop and select, and eventually 1-2 of them will be fully mature and form eggs. Eventually, only 400-500 follicles will develop and ovulate during a woman’s lifetime to form an egg. Mature eggs are fertile and will conceive once they have united with sperm to form a fertilized egg. The vast majority of women have normal ovulation, but some women do have ovulatory dysfunction, most commonly polycystic ovary syndrome.