The Limits to Low Fertility: A Biosocial Approach

Abstract

In light of 30 years of below‐replacement fertility in many industrialized societies, demographers are asking whether fertility could drop even further, or whether there is a “floor” below which it will not fall. A key unanswered question is whether there may be a variable biological component to fertility motivation which ensures that we continue to reproduce. Drawing on evidence from evolutionary biology, ethology, quantitative genetics, developmental psychobiology, and psychology, the article argues that our evolved biological predisposition is toward nurturing behaviors, rather than having children per se. Humans have the unique ability to be aware of such biological predispositions and translate them into conscious, but nevertheless biologically based, fertility motivation. It is likely that we have already reached the limits to low fertility since this “need to nurture,” in conjunction with normative pressures, ensures that the majority of women will want to bear at least one child. A sketch for a biosocial model of fertility motivation is outlined.