The first approach to assessing male fertility is to study a spermiogram, where special attention is given to sperm count, motility and morphology, while less attention is given to other cells in the ejaculate. Normal spermatogenesis requires a balance between cell death and proliferation; therefore, the number of germ cells (GC) in the ejaculate is less than the number of sperm. We propose a new index for altered spermatogenesis, i.e., the rate GC/sperm. We investigated a patient with oligozoospermia and a GC/sperm ratio greater than one, which indicated that spermatogenesis had been damaged. Complementary cytological tests were employed to characterized GC status: Papanicolaou stain, transmission electronic microscopy (TEM), vitality test, AgNOR and TUNEL assay. We also correlated cell morphology with ultrastructure studies that showed apoptosis. Nuclear apoptosis is characterized by vacuolization, misshapen nuclei, and "half moon," dispersed, uncondensed, disrupted and smudged chromatin. Cytoplasmic apoptosis is characterized by vacuolization, cytoplasmic protrusions, lamellar bodies, and swollen endoplasmic reticulum and mitochondria. To date, only testicular biopsy has been used to diagnose complete or incomplete testicular arrest. Our investigation is the first to determine a cytological feature in semen samples that could be used as a biological marker for abnormal spermatogenesis and for predicting the transition from oligospermia to azoospermia.