Potential Mechanisms of Sex Ratio Adjustment in Humans and Nonhuman Mammals

Abstract

There is now substantial evidence that both humans and nonhuman mammals can control offspring sex ratios in response to environmental and social conditions. Yet, because these species utilize a strict system of genetic sex determination, the mechanisms by which mammals may control offspring sex ratios remain elusive. There is evidence that manipulation of offspring sex ratios may occur both before and after fertilization in mammals. As a result, there are many potential targets that could allow for either influences over which sex is initially produced and/or which sex ultimately survives to birth. In this chapter, I will review the many developmental time points during which manipulation of offspring sex ratios could take place in mammals.