Sex Ratios and Long-Term Marriage Trends

In this paper, we ask to what extent changes to the age and sex structure of the population account for the changes in the marriage behavior observed in the United States in the last century (from 1900 to 1980). The decrease in mortality, especially for women, and the changes in immigration patterns have increased the female to male ratio. With respect to marriage, there has been i) an increase in its incidence, ii) a reduction in the gender gap of the median age at first marriage, and iii) an increase in the divorce rate. We pose a model of marriage and divorce in which preferences over spouses depend on their age and on love (an idiosyncratic shock) and where search frictions make it difficult to get new partners. We estimate our model using marital and population patterns of the 1950-1959 birth cohort. Using the preference parameters estimated on the 1950s cohort and the age and sex structure of the 1870s cohort, we find our model can generate marriage patterns which are quite similar to those observed in the earlier period. By making divorce costly for the 1870s cohort, the resemblance is much stronger. In particular, we find that these features account for most of the changes in the marriage behavior observed in the last century; our model explains i) 94.5% of the increase in the incidence of marriage, and ii) 140.8% of the shrink the gender age gap in the median age at first marriage.