The American Society for Reproductive Medicine has recently stated that egg (oocyte) freezing is not considered experimental. Because of this, fertility centres can now freeze eggs for women who may want to use them in the future. Patients who are considering this option can either freeze eggs alone or freeze a combination of eggs and embryos (fertilized eggs) using donor sperm. As of now, the thawing of eggs and subsequent fertilization varies between fertility centres. Embryos are thought to have a better chance of thawing and implanting in your uterus than thawing eggs and attempting to fertilize at a later date.