**8. Conclusion**

Rare sperm freezing is a procedure with wide application and of high value in many aspects to ART, fertility preservation and endangered wildlife conservation. Freezing single sperm cells is still a challenge in modern laboratories. Incredible effort has been set and numerous devices and sperm freezing protocols have been investigated in order to establish the most reliable approach to rare sperm freezing. Despite the great achievements in the area, scientists continue the search for better results.
