ts success, many people[who?] argue that human cryopreservation is unethical. According to certain views[which?] of the mind body problem, some philosophers[who?] believe that the mind, which contains thoughts, memories, and personality, is separate from the brain. When someone dies, their mind leaves the body. If a cryopreserved patient gets successfully resuscitated, no one knows if they would be the same person that they once were or if they would be an empty shell of the memory of who they once were.[improper synthesis?]
Right now scientists are trying to see if transplanting cryopreserved human organs for transplantation is viable, if so this would be a major step forward for the possibility of reviving a cryopreserved human.
Cryopreservation for embryos is used for embryo storage, e.g., when in vitro fertilization (IVF) has resulted in more embryos than is currently needed.
Pregnancies have been reported from embryos stored for 16 years. Many studies have evaluated the children born from frozen embryos, or “frosties”. The result has been uniformly positive with no increase in birth defects or development abnormalities. A study of more than 11,000 cryopreserved human embryos showed no significant effect of storage time on post-thaw survival for IVF or oocyte donation cycles, or for embryos frozen at the pronuclear or cleavage stages. Additionally, the duration of storage did not have any significant effect on clinical pregnancy, miscarriage, implantation, or live birth rate, whether from IVF or oocyte donation cycles. Rather, oocyte age, survival proportion, and number of transferred embryos are predictors of pregnancy outcome.
Cryopreservation of ovarian tissue is of interest to women who want to preserve their reproductive function beyond the natural limit, or whose reproductive potential is threatened by cancer therapy, for example in hematologic malignancies or breast cancer. The procedure is to take a part of the ovary and perform slow freezing before storing it in liquid nitrogen whilst therapy is undertaken. Tissue can then be thawed and implanted near the fallopian, either orthotopic (on the natural location) or heterotopic (on the abdominal wall), where it starts to produce new eggs, allowing normal conception to occur. The ovarian tissue may also be transplanted into mice that are immunocompromised (SCID mice) to avoid graft rejection, and tissue can be harvested later when mature follicles have developed.
Human oocyte cryopreservation is a new technology in which a woman’s eggs (oocytes) are extracted, frozen and stored. Later, when she is ready to become pregnant, the eggs can be thawed, fertilized, and transferred to the uterus as embryos. Since 1999, when the birth of the first baby from an embryo derived from vitrified-warmed woman’s eggs was reported by Kuleshova and co-workers in the journal of Human Reproduction, this concept has been recognized and widespread. This break-through in achieving vitrification of woman’s oocytes made an important advance in our knowledge and practice of the IVF process, as clinical pregnancy rate is four times higher after oocyte vitrification than after slow freezing. Oocyte vitrification is vital for preservation fertility in young oncology patients and for individuals undergoing IVF who object, either for religious or ethical reasons, to the practice of freezing embryos.
Semen can be used successfully almost indefinitely after cryopreservation. The longest reported successful storage is 22 years. It can be used for sperm donation where the recipient wants the treatment in a different time or place, or as a means of preserving fertility for men undergoing vasectomy or treatments that may compromise their fertility, such as chemotherapy, radiation therapy or surgery.
Cryopreservation of immature testicular tissue is a developing method to avail reproduction to young boys who need to have gonadotoxic therapy. Animal data are promising, since healthy offspring have been obtained after transplantation of frozen testicular cell suspensions or tissue pieces. However, none 