As the field of assisted reproduction has advanced, many previously untreatable men are now biological fathers. Although finding sperm in men with obstructive azoospermia is not difficult, locating and retrieving spermatozoa in men with non-obstructive azoospermia remains a clinical challenge, largely because sperm production in these men can be patchy or focal in nature. In response to this challenge, strategies such as fine-needle aspiration (FNA) mapping have been developed to find spermatozoa. This review discusses the history, evolution and current clinical utility and findings with FNA mapping for male infertility). Review of the current literature in the English language on FNA (diagnostic or therapeutic) with a keyword focuses on sperm detection, retrieval, safety and complications. FNA was described in human medicine over 100 years ago. Testis FNA was described 45 years ago and FNA ‘mapping’ of spermatozoa was described in 1997. This comparative review of the literature on sperm detection and complication rates with FNA and open testis biopsy or microdissection procedures suggests that FNA is highly informative, minimally invasive and is associated with fewer complications than other commonly used approaches to sperm detection in non-obstructive azoospermic patients. FNA mapping has gained considerable traction as an informative, ‘testis sparing’ technique for sperm detection in non-obstructive azoospermia. With knowledge of sperm presence and location prior to sperm retrieval, FNA maps can help clinicians tailor sperm retrieval to optimize time, effort and extent of procedures needed to procure spermatozoa in these difficult cases.