This paper explores the determinants of religiosity in a growth model. Religion reduces the time available for labor and the perceived likelihood of hell. A genetic algorithm selects agents’ discount factors based on their parents’ wealth. A higher discount factor increases savings, encouraging wealth accumulation, but also increases the discounted disutility of eternal damnation, incentivizing religion. The model converges to intermediate levels of the discount factor and religion where wealth is maximized. The genetic process selects agents’ level of patience, and the impact on religion is a side effect. Religion thus exists in equilibrium, even if it reduces genetic fitness.