Biological Factors in Fertility

THE prime mover of population growth is self-reproduction, a fundamental biological attribute or capacity of all living things, not shared by non-living matter. The biological mechanisms of reproduction differ considerably in detail from species to species, though basically they are the same in principle throughout the living world. The phylum to which man belongs and of which he’is the pinnacle is so specialized in this aspect of physiological economy that the co6peration of two individuals of different