Research has shown that men with sisters are more emotionally secure than men who don't have sisters. At the same time, women with sisters are more likely to be more confident in social settings.
Now, don't go hugging your sister just yet. In research, correlation doesn't mean causation. That means it hasn't been proven that having a sister causes emotionally secure individuals. It just means there’s a good chance that there's a link.
The research is clear though. Studies suggest that having sisters has a positive effect on your overall mental health. And it nurtures a kinder disposition in the long term.
Men with sisters are more open
In a study, psychologists at the University of Ulster measured the emotional well-being of 571 people with ages ranging from 17 to 25.
The study found that the subjects who grew up with at least one sister were less anxious, better adjusted to challenges, and happier.
According to one of the researchers, it may be a result of sisters helping foster communication and making their siblings more comfortable with their emotions.
It also seems there’s a correlation between people with sisters and more independent people with clearer life goals.
Professor Tony Cassidy, one of the researchers, said, “Sisters appear to encourage more open communication and cohesion in families."
Good mental health
"However, brothers seem to have the alternative effect. Emotional expression is fundamental to good psychological health and having sisters promotes this in families," Cassidy said.
"It could be that boys have a natural tendency not to talk about things. With boys together it is about a conspiracy of silence not to talk. Girls tend to break that down."
Cassidy added that these findings were more pronounced in families with split up parents. "I think these findings could be used by people offering support to families and children during distressing times. We may have to think carefully about the way we deal with families with lots of boys."
Better communicators
Research also shows that men with sisters are more likely to be better at talking to women. Generally speaking, people who have at least one sister are less likely to get divorced.
A similar study from Brigham Young University involving 395 families with more than one child found that having sisters helped fight negative emotions like feeling unloved, loneliness, insecurity, guilt, and fear. The study also showed that receiving a sister’s affection encouraged individuals to become more altruistic and generous as adults.
The research also showed that having brothers is beneficial, too. But only as long as the relationship is less combative and more loving.
Less depression
The study’s lead author, Laura Padilla-Walker, said as much: “Just having a sister led to less depression.”
"Sibling affection from either gender was related to less delinquency and more pro-social behaviours like greater kindness and generosity, volunteering and helping others," she said.
Sisters often play the role of sibling therapists as they are easy to confide in. They eventually become trusted advisors from adolescence to adulthood.
If all goes well between siblings, sisters can be natural confidants and lifelong best friends.