Human Spermatids and Spermatozoa Lacking Acrosomes

Summary. Exclusively round-headed spermatozoa were detected in the ejaculates of four infertile adult males. Electron microscopy of ejaculate and biopsy material demonstrated that all such spermatozoa were devoid of acrosomes. Abnormal acrosomal development, independent of spermatid nuclei, occurred during the differentiation phase of spermatogenesis. The acrosome was incorporated into the Sertoli cell after release of the spermatozoon from the germinal epithelium.