In this chapter, the author describes a decision-making model that is adaptive in that it optimizes reproductive success. She uses the model to investigate the influence of a number of parameters on optimal fertility and inheritance strategies, to see which are likely to produce outcomes similar to those observed in societies undergoing fertility decline. The author also uses a stochastic dynamic model to analyze which combinations of fertility and wealth inheritance strategies maximize the expected number of grand-children. The minimum wealth at which it is optimal to have another baby is significantly reduced, for all family sizes, and fertility above the level seen in the baseline case is predicted. Increasing parental investment in children is the key to decreases in fertility. When inherited wealth makes an important contribution to fitness and the costs of successfully raising children are high, small families are favored.