We all know which kid Mom and Dad liked best, and odds are you're thinking it's not you.
But does that really make a difference? It can, researchers say, but not always the way you might think.
Less-favored children are more likely to be using drugs, alcohol and cigarettes as teenagers, according to researchers at Brigham Young University in Provo, Utah.
But what matters is not how the parents actually treat the children, but how the kids perceive it.
Who's Daddy's girl? Researcher Alex Jensen says he really loves Charlotte, 3, and Olivia, 2, equally. But he couldn't resist staging this photo after researching favoritism in families.
"There's this cultural perception that you need to treat your children the same, or at least fairly," says Alex Jensen, a professor of psychology who led the study, which was published in the August Journal of Family Psychology. "But if kids perceive that it's not fair, that's when issues start to arise."
Earlier studies have found that many if not most parents do have a favorite child. And though parents usually strive to hide that, it's not always successful. That differential treatment has been linked to problems with family relationships and risky behavior in teens.
Jensen (the youngest of six and his mother's favorite, he says), wanted to dig deeper. So he and a colleague tested 282 teenage sibling pairs, ages 12 to 17. He asked each person how parents treated the children overall, who if anyone was favored, and how the family functioned.
They found no correlation between thinking you're the unfavored child and delinquency. There was a correlation between feeling on the outs and substance abuse.
But it's even more complicated than that, the researchers say.
In families that weren't particularly close, the child who felt less favored was more likely to be a substance abuser. The more dramatic the difference they perceived in preferential treatment, the more likely they were to be using.
But when family members were more engaged with each other, the perceived favoritism had less impact, at least when it came to substance abuse.
Obviously there's a chicken-and-egg issue here; teenagers who are more likely to be using substances may just be more likely to see themselves as the odd kid out. Jensen's next task is to try to figure that out.
Parents can try to minimize any ill effects of perceived favoritism by letting the kids know that you really do love them, Jensen says, annoying teenage attitude and all.
"See them as individuals and love them for who they are," he told Shots. "Show them how you love them. Hopefully you do, but try to communicate that love."