Let’s get common knowledge out there before anything else. Sisters are straight-up annoying (I know, I am a sister). They act like they are in charge all the time and always try to have their way. Deep down, you love them fiercely and you would go to the ends of the earth to protect them, but you also wouldn’t mind picking them up and tossing them into the depths of the Mediterranean Sea.
Well, apparently science is saying you have better overall development and more stable mental health if you’ve grown up with a sister. This goes for both male and female children. Sisters keep your mind and emotions running at all times, and since there’s always a heavy dose of sibling love underneath these feelings, they’re tempered to become disciplinary measures that teach kids to have better control of their emotions and mental states.
Sisters make you more expressive and optimistic
A study conducted by the University of Ulster revealed that female siblings can help male children understand how to treat women better . Female siblings foster communication in the family and strengthen bonds between the children.
The study discovered that the soothing and binding influence of sisters is usually invaluable after distressing family events such as the death of a member or divorce. Published in the British Psychological Society, the study involved the assessment of participants by psychological evaluation questionnaires. It was discovered that female children usually aim for peace and unity in the family, trying to get everyone to talk more, express their feelings, and generally stay together.
“Sisters appear to encourage more open communication and cohesion in families,” said Tony Cassidy, lead researcher. “However, brothers seemed to have the alternative affect. Emotional expression is fundamental to good psychological health and having sisters promotes this in families.”
The study from UU also discovered that sisters can help a child to become more ambitious, independent, and goal-oriented. They are usually more caring and supportive than brothers, aiming to steer their siblings toward a stress-free, happy, and comfortable life.
They improve your mental health and self-esteem
A 2010 study published in the Journal of Family Psychology and conducted by the Brigham Young University discovered that a sister’s warm support can improve a child’s mental and emotional health .
The study involved the psychological assessment of 395 different families with both male and female children. Each family had a child or more between the ages of 10 and 14. It was discovered that sisters promote impressive social behavior, morals, and ethics in children, usually having a strong influence of kindness and generosity in their siblings. It also noted that it doesn’t matter whether the female child is the youngest or the oldest in the family.
The study also discovered that sisters help children develop high self-esteem and generally give them a positive mental health boost. Surprisingly when they looked at conflicts between siblings, there was some silver lining. While excessive fighting may have a negative impact by increasing the risk for delinquency long term, small amounts of quarrel actually helped the children to learn how to make amends and recover emotionally, or as many of us say, ‘kiss and makeup.’ 
“What we know suggests that sisters play a role in promoting positive mental health,” said asst. Professor Alex Jensen, author of the research. “And later in life they often do more to keep families in contact with one another after the parents pass. According to the paper, the influence of sisters teaches kids to protect themselves from the unhealthy mental states of “feeling lonely, unloved, guilty, self-conscious and fearful.”
Sisters teach compassion and conflict-resolution
The traits of love and affection are seen on average in sisters tend to promote social behaviors and skills such as compassion, altruism, and conflict-resolution. The study found that sisters teach empathy while their siblings learn how to be nurturing and caring. Bickering with your sister teaches you how to resolve conflicts and get in front of problems before they escalate. Also, a person who has a sister (usually a younger one) is more inclined to learn how to nurture, protect, and guide their sister, always aiming to keep help navigate the harsh realities of life.
Men who grew up with female siblings usually fare better in romantic relationships with women. They’ve spent their formative years with females, so they are more inclined to hold their own in a relationship than men who have never had sisters. They know how to communicate, relate, placate, and retreat when tensions climb too high.
Sisters are amazing and if you have one, hold her close and love her with all your heart.
However, boys aren’t all trouble and headaches. The Brigham Young University study showed that simply being a loving sibling (brother or sister), helped to promote good deeds. This could be anything from helping a neighbor to watching out for other kids at school .
In the end, it doesn’t matter what the genders of our children or siblings are, because let’s face it, that’s something we can’t control. However, that doesn’t mean we give up, as long as we are aware of some of the potential limitations of not having a mixture of sons and daughters, we can most likely make up for it. The moral of the story is this: have as loving as a family as possible, support your fellow siblings, and you’ll probably be ok. Oh and remember, those bumps in the road, they’re normal, just try not to drive off a cliff.