Abstract
Spermiogenesis has been investigated in four cases of agenesia of vasa deferentia. During acrosome formation various anomalies gave rise to late spermatids with deformed heads. Chromatin condensation proceeded normally, but completion of this process appeared to be delayed. Redundant nuclear membranes frequently persisted at the basal region of the nuclei in mature spermatozoa, which occupied niches within Sertoli cells, as the tubules had no lumen. Flagellar structure was normal. These findings support the view that the altered local milieu and variations in acrosome formation may induce the observed anomalies.