Sex and Subsistence: Income Effects on Risky Sexual Behavior and Partner Selection

Whether to engage in sex and with whom are extremely consequential decisions for young women worldwide, and particularly in sub-Saharan Africa, where HIV rates are high and adolescent pregnancies are common. Yet little is known about the extent to which these decisions are financially motivated. We combine a randomized controlled trial of monthly cash assistance to female students at the University of Zambia with detailed, high-frequency data on sexual behavior and partner characteristics. We find that this temporary increase in income significantly changes women's sexual behavior. Treated participants are 5.1 percentage points less likely to have sex during the treatment period, and the rate of condomless sex falls by 30%. Among women who were not sexually active at baseline, the likelihood of having sex falls by 43%, and partner quality conditional on sex greatly improves. Financial assistance also reduces financial precarity, increasing food security, mental health, and cognitive capacity. These results can be rationalized with a dynamic model of partner search in which women can choose to search for boyfriends or high-income partners who provide financial support and bargain over both transfers and condom use. We conclude that a substantial share of sexual activity is financially motivated in this setting, even in a population not typically regarded as vulnerable. Increasing young women's income may be a useful tool for reducing the negative externalities of risky sex and improving match quality.