multi-component cryoprotectant for human sperm and embryos, which is known to be the unique experience in the world.Using this method enabled to create at the Institute (V.I. Grischenko, Luchko N.A., Kalugin Yu.V., Kuchkov I.N.) [1-4] the first in Ukraine cryobank of donor sperm, the material from which is used by the major part of Infertility Centers in Ukraine.
Scientists of the Department study the effect on human spermatozoa of both high and low freezing rates, as well as conduct the research aimed to optimization of the content of cryoprotective and rehabilitative media. Depending on thee cryopreservation regimen (Grischenko V.I., Luchko N.A., Kalugin Yu.V., Kuchkov I.N., Dunaevskaya A.V., Yurchenko G.G.) [2-6].
In addition to cryopreservation, we investigate the biological integrity of spermatozoa (Kramar M.I., Alekseevskaya E.I., Terpyachaya I.V., Yurchenko G.G., Tchub N.N., Pinyaev V.I.) [7-9] and human embryos (Grischenko V.I., Tchoob N.N.) stored under hypothermia conditions. There has been elaborated the method for a short term hypothermic storage of human spermatozoa to be used when treating infertility using assisting reproductive technologies (artificial intrauterine insemination, in-vitro fertilization)..
The data accumulated enabled the scientists (Grischenko V.I., Alekseevskaya E.I.)  to set the concept of cryorenewal of biological objects according to which we succeeded not only to preserve, but also to improve their quality.
One of the aspects of the research work at the department is the search for the stimulation methods of biological activity of native and cryopreserved human sperm (Kramar M.I., Alekseevskaya E.I., Tchoob N.N.) .
In 1987 the scientists of the Department (Grischenko V.I., Dakhno F.V., Tchoob N.N., Pinaev V.I.) initiated the work on human oocyte in vitro fertilization, as a result in 1991 there was born the first girl, the conception of who was accomplished out of the mother's organism.
The investigations performed at the Department greatly contributed the studying the effect of cryoprotectants and freezing regimens on human embryos (Petrushko M.P.) . Zygotes being frozen in 18 hours from the moment of oocytes insemination, were established to be the most cryosensitive ones. Slow cooling with 1.2-propanediol was shown to be the optimum to preserve early-stage embryos. There was for the first time found the influence of cryoprotectants of high concentrations and certain freezing regimens on the appearance of chromosome aberrations, meiosis and mitosis pathologies, changes of synthetic processes in DNA-RNA-protein system in human gametes (Petrushko M.P.) , there was introduced the method for cytogenetic analysis of non-fertilized oocytes and embryos to reveal the failures during IVF program There were chosen the optimal cryopreservation conditions for human embryos of different development stages. As a result of the investigations in 2003 there was born the first in Ukraine child after the transfer to woman of frozen-thawed embryos [13-14].
In gametes, fish and bird embryos the group of scientists of the Department (Prof. Kopeika E.F., Drokin S.I., Cherepanov V.V., Dzuba B.B.) there have been accomplished the investigations in the following directions:
- biology of gametes maturation;
- mechanisms for cell cryodamages and cryoresistance;
- studying the effect of cryoprotectants on cells, of multi-component cryoprotective media and cryopreservation regimens;
- optimisation of the composition of cryoprotective media and cryopreservation, freeze-thawing and insemination regimens;
- reparation of cryodamages.
As a result there were elaborated the ways of sturgeon sperm cryopreservation (Pushkar et al., 1976; Kopeika E.F., Novikov, 1983) [15-17], of carp (Kopeika E.F., 1986) and salmon (Zheltonozhko O.V., Zheltonozhko V.V., Cherepanov V.V., Petrenko A.Yu, 1996) ,being used while creating the first in former USSR two fish sperm banks in Russia and Ukraine (Kopeika E.F. et al., 1989) and during the establishing of salmon sperm cryobank of Kamchatka.There was elaborated the method for sturgeon sperm hypothermic storage (Blokhin C.V., Kopeika E.F.) [22-24], as well as the role of oocyte in reparation of cryodamages (Kopeika J. et al., 2003) . There were studied the metabolic processes of carp and salmon sperm prior to and following cryopreservation (Cherepanov V.V., Dzuba B.B., Kopeika E.F.) [26-27].There was established the link of sperm cryoresistance with the spawning medium tonicity and cholesterol/lipids ratio in membranes (Drokin S.I., Kopeika E.F., Grischenko V.I., 1989) , and with changes in cells volume (Dzuba B.B., Kopeika E.F., 2002) .When studying the mechanism of a rainbow trout spermatozoa cryodamage on cell membrane surface there was found an ultra-rapid lateral diffusion of membrane particles and cluster formation (Drokin S., Stein H., Bartscherer H. , 1998) .