What does the link between infertility risk and marriage timing look like? This study investigates whether exposure to an infertility-causing strain of the parasitic disease schistosomiasis affects the probability of child marriage in Madagascar. Findings reveal that exposure to the infertility-causing strain increases infertility risk by up to 20–40 percent and raises the likelihood of child marriage by up to 22 percent. Similar impact has been found on adolescent births. The results also indicate that women exposed to this strain are less likely to have any education at all.