Oogenesis is the process by which female gametes, or eggs, are produced in the ovaries. It begins before birth, with the formation of primary oocytes that remain dormant until puberty. Each month, during the menstrual cycle, a few primary oocytes resume development, ultimately leading to the maturation of one egg. During oogenesis, the primary oocyte undergoes meiosis, a type of cell division that reduces the chromosome number by half. This process results in one functional egg and smaller polar bodies that typically degenerate. The completed egg is then released during ovulation, ready for potential fertilization by sperm from the male gamete, or spermatozoon.