This method is indicated in cases of men with severe oligoasthenoteratozoospermia as well as azoospermia (absence of spermatozoa). With testicular biopsy (TESE and micro-TESE) we are able to retrieve sperm directly from the testes. The classic testicular biopsy (TESE), which accesses testicular tissue, is the method that has been used all these years. Micro-TESE is the evolution of the method and involves retrieving sperm from the seminiferous tubules using a special microscope. In this way the rate of finding sperm is increased compared with the classic method. It is considered a low-severity procedure, performed under light anaesthesia, and no hospital stay is required.