**8. Injection with immature sperm**

Round spermatid nucleus injection (ROSNI) or round spermatid injection (ROSI) is a method in which precursors of mature sperm obtained from ejaculated specimens or testicular sperm extraction (TESE) are injected directly into oocytes. ROSNI is proposed as a treatment for men in whom other more mature sperm forms (elongating spermatids or sperm) cannot be identified for ICSI [72]. It is not widely performed, not as successful as ICSI and is still an experimental procedure. It should be applied only in the setting of a clinical trial approved and overseen by a properly constituted institutional review board. Accurate identification of round spermatid is a technical challenge of ROSNI. It is difficult to distinguish haploid round spermatids from diploid spermatogenic precursors and somatic cells using the standard optics present in most clinical IVF laboratories. Mouse round spermatids have increased levels of DNA fragmentation [73] that may interfere with fertilization [63]. Increased DNA damage may occur because of deficient sperm nuclear protamine to histone replacement and decreased nuclear condensation in these immature sperm allowing increased susceptibility to reactive oxygen species and other damaging agents in culture. Another major concern is genetic risk. Any genetic abnormality sufficiently severe to result in meiotic arrest during spermatogenesis may also have adverse effects on other normal cellular processes or other systemic manifestations. Occurrence of significant congenital anomalies in ROSNI-conceived pregnancies raises serious concerns [74]. ROSNI should not be performed when more mature sperm forms (elongating spermatids or sperm) can be identified and used for ICSI. Patients who may be candidates for ROSNI should receive careful and thorough pre-treatment counselling to ensure they are clearly informed of the limitations and potential risks of the procedure [75].
