**4. Conclusions**

For many years, scientists have made every endeavour to develop laboratory assays that precisely estimate the fertilizing capacity of semen. Laboratory semen appraisals can be classified in several ways. Nevertheless, an important factor for a laboratory analysis to be useful, it must be objective, repeatable, accurate and as far as possible, rapid. Among others, there can be distinguished one major division into conventional methods and advanced techniques of sperm assessment. It is little questionable, whether the subjective assessment of parameters related to the functional and morphological characteristics of spermatozoa, would increase the predictability of the fertilizing potential of cryopreserved semen. However, conventional methods for sperm evaluation in connection with the more objective computer-assisted sperm analyzers, flow cytometry and in vitro fertilization tests, have enabled researchers to gain accurate information about the morpho-functional status of spermatozoa and mechanisms of sperm cryoinjury.
