Thanks to advances in new freezing techniques, Israeli scientists have successfully transplanted whole frozen and thawed ovaries in sheep, retrieved oocytes from these ovaries and triggered them in the laboratory into early embryonic development, research that could "revolutionise the field of cryopreservation". The team, led by Dr Amir Arav, a senior scientist at the Institute of Animal Science, Agricultural Research Organisation in Bet Dagan has been able to demonstrate long-term intact organ cryopreservation with restored function following thawing and transplantation of the ovaries of eight sheep using a technique that they have developed based on Multi-Thermal-Gradient (MTG) freezing. The freezing apparatus which moves at a constant velocity through a thermal gradient producing a controlled cooling rate has the ability to control ice crystals propagation by changing thermal gradient or the liquid-ice interface velocity which optimises ice crystals morphology during the freezing of cells and tissue. This apparatus allows for freezing with normal post-thaw motility/pre-freezing motility of 70-100%. The experiment was a success, resulting in five successful transplants. In all, six oocytes were obtained and developed into eight cell embryos.