INCIDENCE AND IMPLICATIONS OF ALTERED SEMEN QUALITY ON FAMILY-PLANNING

Alterations in the expression of the human genome, or interference wit h its products, can be induced in the male reproductive system by chem icals mimicking or antagonizing naturally occurring hormones. Opportun ities exist for disruption at the hypothalamus, pituitary and testis l evels. Recent concerns generated by the increased incidence of testicu lar cancer, congenital anomalies of the male genitalia and possible al terations in human semen quality have been linked to the environment. The report by Carlsen in 1992 [1] suggested that semen quality has det eriorated over the past six decades. More recent reports suggest that the decline may be globally non-uniform and regional in nature. The ef fects of any such declines upon overall pregnancy rates are generally unknown, although some studies have attempted to address them. A preli minary review of the impact of a small decrease in sperm concentration s suggests that a directly measurable reduction in fecundity does not occur, but that future problems could be anticipated. Decrements in se men quality will alter the epidemiological probabilities of pregnancy due to coitus on different cycle days and may thereby change the durat ion of the fertile time. Current understanding of the implications of altered semen quality on relative fertility is not sufficient to chang e our current teaching and practice of NFP.