Microfertilization is probably the most important embryology technique, as it gives couples with significant male factor infertility the opportunity to achieve their goal. It is a very fine procedure that requires specific maneuvers and equipment, so as to eliminate the risk of injury to the eggs. The Olympus SLICSI system consists of a complex polarized light lens mechanism, which allows us to clearly detect the egg spindle (DNA spindle) during microfertilization. It minimizes the risk of injury when introducing the sperm to the interior of the egg. In addition, the SLICSI system allows us to use larger magnification in the microscope, so as to select morphologically smoother sperm.