The Sex Ratio and the Out-of-Wedlock Birth Rate in the United States during World War II

Abstract

This paper provides a theoretical economic framework to study the effects of changes in the sex ratio on the out-of-wedlock birth rate in the United States. We model the demanders and suppliers of sexual relations as potential mates and the relative “price” of human sexual relations as the promises implicit within a traditional marriage (marriage, fidelity, wealth transfers, child support, etc.). We examine an instrument for the implicit “price” of sexual relations, namely the out-of-wedlock birth rate. We show that the reduction in the number of available sex partners for women during World War II decreased the “price”—in terms of marriage—that remaining men had to pay for sex. One result of this lower “price” is an increase in the number of children born out-of-wedlock during the war. According to our regression results, a reduction in the sex ratio of 10 males per 100 females in the U.S. population during World War II increased the out-of wedlock birth rate by six to ten percent.