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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.
The X chromosome may be as important as the Y in determining male fertility potential. By refining the analysis of the particular recombination abnormalities in infertile men, this study confirmed that there may be decreased chromosomal pairing quality as well as recombination frequencies in men with non-obstructive azoospermia. Documentation of the normal variability in recombination is a prerequisite for the understanding of changes observed in abnormal situations, such as non-disjunction or a chromosome re-arrangement. It appears that G-group as well as sex chromosomes are most susceptible to having no recombination foci and thus are more susceptible to non-disjunction during spermatogenesis. The growing knowledge of the close relationship between germ cells and stem cells, and the successful manipulation of these cells in vitro, has tremendous implications not only for the treatment and cure of male infertility but also for a host of other medical diseases in the future.