Oogenesis is the production of egg cells inside the ovaries. During foetal development, few germinal cells in human ovary differentiate and divide mitotically to produce egg mother cell/oogonia. Further, oogonia become larger and divide to produce diploid primary oocyte. In follicular prenatal phase, the primary oocytes start first meiotic division but are transitionally suspended into prophase stage of meiosis I and are stored in the follicle. After puberty, primary oocyte resumes the division and completion of first meiotic division produce one secondary oocyte (egg cell) and one polar body (non-functional cell).