Although parents often try not to favor one child, we examine whether specific environmental factors might bias parents to favor children of one sex over the other. This research draws on theory in evolutionary biology suggesting that investment in female versus male offspring depends on resource availability. Applying this to consumers, a series of experiments show that poor economic conditions favor resource allocations to daughters over sons. For example, poor conditions led people to bequeath more assets to girls in their will, and to choose girls to receive a US Treasury bond and a beneficial extracurricular activity. It is proposed that this happens because spending on children represents a reproductive investment, and that boys’ and girls’ relative reproductive value varies with economic conditions. Supporting this account, perceptions of which child will have more children statistically mediates the effect of economic conditions on preferences for girls. Consequently, the effect is strengthened as a child approaches reproductive age, and it is moderated by individual differences (risk aversion and monogamy) directly related to our theoretical model. This research contributes to the consumer behavior literature by revealing how, why, and when environmental factors influence spending on girls versus boys.