“…Patients with sickle cell disease often have moderate to severe hypogonadism, [9][10][11] of unknown origin, although several mechanisms have been suggested: primary hypogonadism, 9,12 hypogonadism induced by repeated testicular infarction, 13 zinc deficiency, 14,15 and puberty delay due to span-height retardation. [16][17][18] Hydroxyurea itself has been reported to impair spermatogenesis in mammals, resulting in testicular atrophy, 19-21 a reversible decrease in sperm count, [19][20][21][22][23] and abnormal sperm morphology 20,24 and motility. 19 Furthermore the chromatin structure of germ cells is also affected, mainly in preleptotene spermatocytes 20,21 and apoptosis is increased, essentially in spermatogonia and early spermatocytes 25 while stem spermatogonia do not seem to be affected, resulting in the possibility of repopulation of seminiferous tubules.…”