Beauty, Polygyny and Fertility: Theory and Evidence

We propose a simple model of a mating economy in both monogamous and polygynous cultures, and derive implications for how polygyny affects individual and aggregate fertility. We find that an attractive woman is more likely to find a high-status husband. However, when polygyny is allowed, high-status husbands naturally attract other women; this implies that female beauty increases the likelihood of entering into a polygynous relationship. A woman in a polygynous relationship produces fewer children than a woman in a monogamous relationship as long as the preference for reproduction relative to consumption is not too strong. However, the societal practice of polygyny increases aggregate fertility through two distinct channels: (1) by increasing the number of marriages; (2) by triggering fertility contagion: a woman, whether involved in a monogamous or polygynous relationship, produces more children as polygyny becomes more prevalent in her neighborhood. We empirically validate each of the model's key predictions.