The document discusses several methods for preserving fertility in cancer patients, including: 1) Embryo freezing and ovarian tissue banking which allow patients to preserve eggs or embryos before cancer treatment. 2) The use of gonadotropin-releasing hormone agonists (GnRHa) during chemotherapy to protect ovarian follicles, based on a preliminary study showing it effectively preserved fertility. 3) Cryopreservation of immature or mature eggs, though success rates for mature egg freezing are still low due to challenges with ice crystal formation during slow freezing methods. New vitrification techniques may improve survival rates.