The Demography of Subfecundity

A populations fecundity is the average fecundity of its individual members. The relative contribution of the male and female disorders to subfecundity is difficult to pinpoint. It is estimated that male subfecundity accounts in whole or in part for 20% to 60% of the subfecundity in various populations. In the US the concensus is that men contribute to subfecundity in 30% to 40% of the cases and the women in 60% to 70%. The actual fertility of almost all populations ranges from only 1 to 8 children/women; with about 4 being the world average in 1982. In addition to subfecundity a societys fertility level is determined by various forms of birth control and by the fact that much of an individuals reproductive period is spent without regular coital activity. 1 task of fertility studies is to determine the relative impact of subfecundity birth control and mate exposure factors that are characterized as intermediate variables. Subfecundity has depressed fertility since the human race began. It is also an important fertility determinant in contemporary developing societies. The prevalence of subfecundity in these societies is given especially Africa and Asia. Improvement in health during modernization might lead to a reduction of subfecundity and to a subsequent rise in fertility. Health manpower by occupation rate/100000 population and density is given in charts. Subfecundity factors are still demographically important in developed societies. The prevalence of subfecundity for these societies is given especially for the US and its impact on fertility discussed. Life expectancy at birth is an important measure of a populations health. Effect of timing on fertility is discussed as is the ability of subfecundity to influence fertility behaviorally through the other intermediate variables. These are: 1) phase of fertility and 2) subfecundity-birth control-mate exposure categories. A research project identified 5 categories of factors which influence population subfecundity: 1 psychopathology; 2) disease; 3) nutritional deficiencies; 4) environmental factors; and 5) genetic factors.