Lack of a head in human spermatozoa from sterile patients: a syndrome associated with impaired fertilization.

Three patients with primary sterility in whom the majority of spermatozoa lacked a normally implanted head are presented. A small cephalic knob was evident in most of them by routine colorimetric techniques, and the Feulgen reaction failed to show any deoxyribose nucleic acid. The morphologic features of the tails was normal.