Why Having a Sister Makes You a Kinder Person

Aug. 5, 2010 — -- Long before she vowed to improve the health of American children, First Lady Michelle Obama made Craig Robinson a better person just by being his little sister Miche.

Simply by being a sister, Susan G. Komen inspired her sibling to be a more generous person too – eventually leading a worldwide crusade that has raised $1.5 billion for breast cancer research.

New research shows that having a sister – even one who pinches and tattles but also shares her ice cream cone – makes you a kinder, more giving person.

The study has found that adolescents with sisters feel less lonely, unloved, guilty, self-conscious and fearful. Regardless of whether she is older or younger, a sister has a far stronger influence than parents on a person's mental well-being.

"Just having a sister led to less depression," said Laura Padilla-Walker, a professor in Brigham Young University's School of Family Life and lead author on the study published in this month's Journal of Family Psychology.

For Robinson, head coach at Oregon State University, a close relationship with his only sibling Michelle, two years younger, included sharing a bedroom separated by a divider. Not only his roommate but his confidante, Miche, as he calls her, was upset that their parents smoked and once conspired with him to destroy every cigarette in the house.

Nancy Brinker and her sister Suzie, three years older, grew up as best friends. "Suzie was the Queen Bee of the neighborhood but she had her mischevious side. When she was grounded, I was the hostage negotiator. When she exceeded her curfew, I was the peace envoy. When Suzie died, my life's work was born," said Brinker, founder of Susan G. Komen for the Cure.

The study showed that brothers have benefits, too, as long as the relationship is more loving than combative.

"Sibling affection from either gender was related to less delinquency and more pro-social behaviors like greater kindness and generosity, volunteering and helping others," Padilla-Walker told ABC News.

In fact, the link between sibling affection and good deeds is twice as strong as the link between parental love and good deeds.

Nancy Brinker, inspired by her sister Susan to lead the fight against breast cancer.