An alternative option in fertility preservation is embryo freezing. Although egg freezing success rates are improving, we see higher success rates with embryo cryopreservation. Once the eggs are retrieved, the mature eggs are fertilized with partner or donor sperm. These high quality embryos remain frozen until the patient is ready to use them. If patients have completed their families, they have the option of donating these frozen embryos to research, another couple or training; the embryos can also be discarded.