An unusual abnormality of human spermatozoa.

An unusual abnormality of human spermatozoa is reported. A 33 year old man presented at the clinic after 6 years of involuntary infertility. The patients semen was examined with the light microscope and 90% of the spermatozoa were abnormal with round heads. Most of the spermatozoa had a detached tail which was still motile. Thick sections of the spermatozoa were prepared and examined with the electron microscope. The abnormal round-headed spermatozoa often showed eccentric implantation plates double tails and thickened midpieces. A testicular biopsy showed disorganization of the normal clonal pattern of development in many of the seminiferous tubules and confirmed the lack of normal spermatozoa. This defect may be caused by a developmental abnormality at the spermatid stage.