Sociologists Dalton Conley and Emily Rauscher claim:
Using nationally-representative data from the  General Social Survey, we [Conley and Rauscher] find that female offspring induce more conservative political identification. We hypothesize that this results from the change in reproductive fitness strategy that daughters may evince.
But economists Andrew Oswald and Nattavudh Powdthavee have found the exact opposite:
We [Oswald and Powdthavee] document evidence that having daughters leads people to be more sympathetic to left-wing parties. Giving birth to sons, by contrast, seems to make people more likely to vote for a right-wing party. Our data, which are primarily from Great Britain, are longitudinal. We also report corroborative results for a German panel.
How to resolve these? See here.