Washington, Aug 3 (IANS) The presence of a sister - even younger - seems to shield 10 to 14-year-olds from depression and loneliness.

A sister protected adolescents from feeling lonely, unloved, guilty, self-conscious and fearful. It didn't matter whether the sister was younger or older, or how far apart the siblings were age-wise, a study by Brigham Young University said.

In fact, loving siblings fostered charitable attitudes more than loving parents did. The relationship between sibling affection and good deeds was twice as strong as that between parenting and good deeds.

Brigham Young professor Laura Padilla-Walker led the study, which also sorts out the influence of siblings and parents within families, a Brigham release said.

Padilla-Walker's research stems from the university's 'Flourishing Families Project', scheduled for publication in the Journal of Family Psychology.

'Even after you account for parents' influence, siblings do matter in unique ways,' said Padilla-Walker, who teaches in Brigham's School of Family Life.

'They give kids something that parents don't,' she said.

The study included 395 families with more than one child, at least one of whom was an adolescent between 10 and 14 years old.

Brothers too mattered. The study found that having a loving sibling of either gender promoted good deeds, such as helping a neighbour or watching out for other kids at school.

Many parents justifiably worry about the seemingly endless fighting between siblings. The study found hostility was indeed associated with greater risk of delinquency.

Yet Padilla-Walker also sees a silver lining in the data: The fights give children a chance to learn how to make up and regain control of their emotions, skills that come in handy down the road.

'An absence of affection seems to be a bigger problem than high levels of conflict,' Padilla-Walker said.