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

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¡±¡ªin terms of marriage¡ªthat 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.