Conservation of sperms: current status and new trends.

Preserving genetic resources for next millennium is of great importance, whereas the major contribution of conserving sperms has the potential in many applications such as agriculture, biotechnology, species conservation and clinical medicine. Two major systems (liquid and frozen) of storage technologies have been developed for sperm conservation until the 20th century. The combinations of storage temperature, the cooling rate, chemical composition of extender, cryoprotectant concentration and the hygienic control are the key factors that affect the life span of spermatozoa. In the past decades, a slow progress have been made in improvement of storage technology, however, the recent advancement in reproduction technology and well understanding of the reproductive physiology have opened the door to a new era in conservation of sperm. This paper focuses on current sperm conservation systems as well as alternative strategies that would be effective for preserving genetic resources in future.