Sperm morphology assessed by strict criteria, along with other male-factor analyses, was reported to be a good predictor of fertilization. Strict criteria for sperm morphology have been widely accepted, their usefulness remains an issue of contention. Sperm morphology assessed by strict criteria, along with other male-factor analyses, was reported to be a good predictor of fertilization. Improved sperm morphology observed surgical correction of varicocele, is probably the result of influencing spermatogenesis. Sperm morphology tends to vary less than sperm count and sperm motility in the same male. Morphology, count, and motility may be likened to a fingerprint, except when some acute process produces a temporary change, and morphology may therefore be an indicator of the health of the germinal epithelium. In the absence of other male or female factors, a very high percentage of spermatozoa need to be abnormal before strict criteria can provide a definitive assessment of infertility.