Embryos are frequently cryopreserved and can remain viable upon rewarming. At this point in time, no person developed beyond the embryo stage has been revived from temperatures far below freezing. Cryonics patients are cared for in the expectation that future technology will be available to reverse damage associated with the cryopreservation process. As an important proof of concept, rabbit kidneys have been cryopreserved, rewarmed, and implanted into the animal and continued to function.