Currently, infertility affects up to 140 million people worldwide. It is considered that the male factor is responsible for nearly a half of problems in obtaining pregnancy. Increasingly, infertility treatment clinics, as well as standard examinations, also offer genetic tests in the diagnostics of the male infertility factor, such as: karyotype analysis, detection of Y chromosome microdeletions, and examination of the chromosome composition of sperm by the fluorescent in situ hybridisation method (FISH). Genetic factors, defined to date, which cover both chromosomal aberrations and monogenic disorders, are responsible for approximately 10–15% of cases of male infertility. Usually, their phenotypic manifestations are disorders in spermatogenesis, structural changes in the genital organs (e.g. reduced size of the testicles), or sperm dysfunction. Molecular studies intensively carried out in the area of diagnostics and treatment of infertility indicate an increasingly large number of relationships between genetic factors and fertility; however, many genes related with human fertility still remain unidentified.