Intracytoplasmic sperm injection (ICSI) is a method commonly used in human medicine in centers of assisted reproduction for artificial insemination in couples who have difficulty conceiving a child. In ICSI, the sperm is directly injected into the oocyte (egg), where it forms a normal male pronucleus, just like in natural fertilization. The possibility of using low-quality sperm for ICSI allows the use of sperm from endangered species and genetic resources. Interspecific ICSI, where sperm is injected into an oocyte of another, easily obtained species, appears to be a simple tool for testing the quality and fertilizing ability of sperm of genetic resources.