Very broad potential application of cryopreserved oocytes in medicine (treatment of infertility , oocyte donation , etc.) , in veterinary medicine and animal husbandry (extension of genetic potential of females ) , ecology (creation of banks oocytes animal species threatened with extinction) and finally in doświadczalnictwie (eg the use of oocytes or cytoplastów cloning ) have until recently been restricted to the limited efficacy of cryopreservation methods .