My sister is 18 months younger than me – and she is literally my best friend in the world. 

Because not only do we share genes and parents – we also share a history, values, memories, ups and downs. And now, as we have had five children between us in the space of seven years, we also share the experience of motherhood – and it is amazing. Sisters are your forever soulmate, built-in best friend and most powerful support system. What's new you ask? Well, it actually turns out that having sisters makes you a better person. Researchers from Brigham Young University found that having sisters boosts your mental health and self-esteem, and that people with sisters find themselves striving to protect them from “feeling lonely, unloved, guilty, self-conscious and fearful”. And obviously, working so hard to protect someone from those kinds of feelings makes you a more nurturing, empathetic person. This is what assistant professor Alex Jensen from Brigham Young University, who has written several studies on sibling relationships, had to say about the study: “What we know suggests that sisters play a role in promoting positive mental health,” Jensen explains. “Later in life they often do more to keep families in contact with one another after the parents pass.” And don't worry if you tend to get into arguments with your sister – these are also good for both of you. “They help you develop social skills, like communication, compromise and negotiation, even sibling conflict, if it is minor, can promote healthy development.” Oh – and brothers benefit from having sisters, too. Now, how's that for girl power?!