How do fertility transitions affect children’s resource endowments? Existing perspectives provide two seemingly different answers: Dilution arguments focusing on family size predict an average gain, while divergence arguments focusing on family structure predict increased inequality. We attempt to integrate these two perspectives, to show how changes in family size and structure additively and interactively shape the levels and inequality in children’s resource endowments. Failure to consider these interactions can severely bias estimates of the magnitude or even direction of the influences of fertility transitions. An empirical illustration is provided with Cameroon data.