Parents spend a lot of time dealing with arguing and other nastiness between siblings. But having siblings can save teenagers from negative emotions, and encourage them to be more kind and generous.
Padilla-Walker studied 395 families that had at least one child between the ages of 10 and 14, interviewing family members twice, one year apart. The study, which was published in the August issue of the Journal of Family Psychology, found that having an affectionate teenage sibling helped younger teens avoid feelings of loneliness, guilt, and self-consciousness. The results were adjusted to remove the effects of parental influence.
Sisters were more likely to have a positive influence than brothers, perhaps because they tend to talk more than boys do. "Sisters seem to be uniquely powerful," Padilla-Walker says. "It could be that sisters act as a sounding board at a time when adolescents don't talk with their parents."
Parents can encourage that kind of supportive relationship by fostering loving, generous behavior in childhood, Padilla-Walker says. Previous research has shown that hostile relationships between siblings correlate with delinquency, so parents need to make it clear that hostility won't be tolerated.
What about only children? "We have some stereotypes about only children, that they're selfish," Padilla-Walker says, "but there's very little research to support that." Parents who want their onlies to have the supportive benefits of a loving sister should make sure their child has lots of interaction with friends and peers, she says, so they have many chances to practice their social skills. Power up those playdates!