EDITORIAL COMMENT Previous studies showed that, compared with men with late maturation arrest (MA), men diagnosed with early MA had a decreased sperm recovery rates by testicular sperm extraction (TESE). In this study, the authors classified patients with non-obstructive azoospermia (NOA) as either early or late, and focal or diffuse and compare sperm recovery rates by a single surgeon using micro TESE operation technique. Early MA was defined in patients whose pathology results showed spermatogenetic arrest at the spermatogonia or spermatocyte stage; and late MA in those arrest occurred at spermatid stage. On biopsy, MA may also vary in its heterogeneity from focal to diffuse pattern in whole seminiferous tubule of the pathology sample. The authors concluded that men with late and focal MA have a higher sperm recovery rate as compared to men with early and diffuse MA. In the presence of MA pathology, a high level of follicle-stimulating hormone (FSH) may predict heterogeneity of testicular tissue. The authors advise the clinicians to be aware of those men with normal FSH and normal testicular volume, with NOA, may have particularly poor sperm recovery rate.