A study from Loyola Marymount University and Stanford Graduate School of Business shows that men who grew up with sisters tend to be more conservative, and to vote Republican in their younger years. The report found that boys with only sisters were 13.5% more conservative in their views of female roles than boys with brothers.
The researchers stated that young men with sisters tend to allow sisters to do all the housework, teaching “boys that housework is simply women’s work.” The effect of having sisters diminished over time politically. The researchers theorized, “We might expect that boys would learn to support gender equity through interactions with their sisters. However, the data suggest that other forces are more important in driving men’s political attitudes, including whether the family assigned chores, such as dishwashing, according to traditional gender roles.” They concluded, “the gender stereotyping of the childhood environment thus may help to explain the effects that sisters have on male political attitudes.”