A procedure in which sperm cells are removed and either used right away to fertilize eggs or frozen for future infertility treatment. Tissue is removed from the testicle through a small incision (cut) and looked at under a microscope in the laboratory to find sperm cells. Testicular sperm extraction may be useful for men who want to have children after having treatment that may cause infertility, such as certain cancer treatments. Testicular sperm extraction is a type of sperm retrieval method. Also called TESE.