Do mothers spend more on daughters while fathers spend more on sons?

Do parents favor some children over others? The overwhelming majority of parents state that they treat their children equally, but parents rarely track their spending on each child. We investigate in four studies whether mothers and fathers favor specific children depending on the biological sex of the child. Evidence from the field, laboratory, and community (online panel) showed that parents exhibit systematic biases when forced to choose between spending on sons and daughters. Mothers consistently favored daughters, whereas fathers consistently favored sons. For example, parents were more likely to choose a real prize and give a real U.S. Treasury bond to the child of the same sex as themselves. These parenting biases were found in two different cultures and appear to be driven by parents identifying more strongly with children of the same sex as the parent.