What is oogenesis?
Oogenesis, or female gametogenesis, is the process by which the oocyte develops. Before birth, there is a migration of primordial germ cells towards the ovaries of the fetus to give rise to primary oocytes through successive mitotic divisions.
Once puberty is reached, these primary oocytes transform into secondary oocytes through meiotic divisions. Finally, the mature egg is produced when it is penetrated by the sperm.
Thus, female oogenesis begins before birth but lasts until fertilization occurs.