As you can see in the figure below, fathers of first daughters are more likely than fathers of first sons to support all the gender equity policies we asked about, including Title IX, enforcement of prohibitions on sexual harassment and gender pay equity. On average, men with first daughters show five percentage points more support for gender equity policies. But what happens when we control for other factors that may shape men’s gender equity attitudes?

To examine this question, we created an index of our three gender-equity policies and ran a statistical model that controlled for the factors listed above. We found that whether a father has a first daughter is among the most important factors accounting for men’s support for these policies – more significant than age, race, education, religiosity, whether a man has a sister or whether a man is married. Specifically, we find that fathers with first daughters, relative to fathers with first sons, are 11 points more likely to express support for our index of gender-equality policies. Notably, we consistently found that simply having a daughter in the family doesn’t affect fathers’ support for gender equity policies. Neither does it matter whether a father has more or fewer daughters than sons. It’s the sex of the first child that makes the difference.

This first daughter effect is unique to fathers; we do not find that having a daughter as a first child influences mothers’ attitudes.