Influences on women's reproductive lives - Unexpected ecological underpinnings

Modern women's reproductive lives vary considerably, in a patterned fashion. Although cultural factors are important, across societies - even across species there exist strong patterns predicted by life history theory. For example, the shorter life expectancy e(0) is at birth, the earlier it pays in biological terms to reproduce. Few factors analyzed in women's life patterns in more than 170 nations influence the divergence. Studies on other species assume that ( a) the variation is species specific and ( b) the conditions are at equilibrium; the relationship between life expectancy and age at first birth is strong, but varies across populations, and is frequently not at equilibrium. Human patterns, like those of other species, may have ecological or life history underpinnings. The answers we find may have policy implications for women's lives and fertility.