A recent study has discovered that those of us with sisters tend to be naturally happier people.
Researchers from De Montfort University in Leicester and The University of Ulster recently surveyed over 570 people aged between 17 and 25.
They were asked psychological questions on various topics including mental health.
The findings discovered that those people who had sisters felt more encouraged to talk about their feelings, making them more "optimistic."
Speaking about the study, Professor Tony Cassidy, said:
"Sisters appear to encourage more open communication and cohesion in families. However, brothers seem to have the alternative effect."
"Emotional expression is fundamental to good psychological health and having sisters promotes this in families."
"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."
"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."