Couples who are impotent to conceive naturally after a year of regular unprotected sexual course, are considered infertile. Infertility is a condition caused by female factor, male factor or both factors working together. Some of the factors that have demonstrated to have an impact in human fertility are: environmental factors, lifestyle, age, infections and diseases, etc.

Male infertility is mostly diagnosed with poor semen analysis and it can be due to genetic defects that increase when spermatogenesis is seriously altered. Spermatogenesis is the sperm formation process that takes place in the seminiferous epithelial tissue. This process is regulated by the gene expression in the germ cells. The abnormal expression of these genes can be caused by testicular, pre-testicular or post-testicular failure. Genetic disorders of chromosomal genes cause azoospermia in infertile patients and are either linked to the X chromosome or originate from the Y chromosome microdeletions.  Studying of the genetic mutations that affect spermatogenesis and accordingly fertilization, is essential not only for the investigation of the unexplained infertility but also for providing better animal models for further human research.