The majority of IVF procedures is performed by means of ICSI technique, where an egg cell is fertilized by introducing a single sperm to each oocyte under microscope. This is why the selection of a proper sperm for fertilization is so important. The basic method of sperm selection is microscopic evaluation – we assess the sperm shape and motility; this is the case with ICSI technique. When using the IMSI technique, we look at sperm in much higher magnification; then we can see in detail the shape of the sperm’s head and its potential damages, craters on the surface of the sperm head which inform us about the likely damage to the genetic material. More advanced methods used in fertilization for the selection of male gametes include FAMSI, where we not only look in detail at the sperm cell but also observe its activation through the evaluation of birefringence or we use the dynamic high pos test, where the sperm’s shape after its stay in hypoosmotic environment tells us indirectly about the quality and function of this sperm cell.