Whether you borrowed their clothes or wrestled with them in the backyard, your siblings helped make you who you are. That sometimes love-hate relationship may change through the years, affected by birth order and our respective personalities. But all in all, brothers and sisters are pretty much in it for the long haul.

"From the time we’re born, our brothers and sisters are our collaborators and co-conspirators, our role models and our cautionary tales. They are our scolds, protectors, goads, tormentors, playmates, counselors, sources of envy, objects of pride," writes Jeffrey Kluger in “The Sibling Effect: Brothers, Sisters, and the Bonds That Define Us.”

Were you the role model or the bratty tagalong? Did you get on each other's nerves or have you been lifetime best friends? Wherever you are on the relationship scale, here are seven interesting sibling facts. Bring them up at the next family dinner.

1. You're less like the siblings who are closest to you in age.

Researchers call it "de-identification." We want to set ourselves apart from the siblings closest to us in the family. So if you're the third kid and the second child is the class clown, you're more likely to be responsible and smart like the oldest in the family.

2. Oldest sibs study; younger sibs take risks.

Firstborns tend to have higher IQs than their younger siblings. Studies say it's because they get a lot of their parents' undivided attention — and that attention drops as more kids get added to the family dynamic.

Wanting to differentiate themselves from their smarter, older siblings, later born kids often lean toward sports — especially risky ones. In an analysis of 8,340 participants in two dozen studies, later born siblings were found to be 1.5 times more likely than firstborns to engage in dangerous sports such as rugby, football and soccer, whereas firstborns and only kids preferred safer sports such swimming, tennis and track.

Interestingly, the same study looked at 700 brothers who played professional baseball since 1876. Younger brothers were more than 10 times as likely as their older brothers to attempt to steal more bases (and they were better at doing it without getting thrown out).

3. Brothers and sisters teach each other.

We learn from everyone in our family as we grow up, says Laurie Kramer, professor of applied family studies at the University of Illinois at Urbana-Champaign, but our parents are better at instructing us how to act in more formal settings like the dinner table and greeting strangers. Our siblings teach us how to survive on the streets (or the subdivision) — like how to act at school or how to be cool. You learn how to argue with your brother and later use those conflict resolution skills in the classroom, in the boardroom and in your grown-up relationships. Heck, little kids even learn to talk (and curse) from older siblings.

“Siblings are closer to the social environments that children find themselves in during the majority of their day, which is why it’s important not to overlook the contributions that they make on who we end up being,” Kramer says.

4. Siblings fight … a lot.

Some experts estimate, through observational studies, that siblings fight about every 17 minutes when they are children. Kramer told Time that, on average, brothers and sisters between 3 and 7 years old have some type of disagreement or conflict about 3.5 times an hour.

Of course, humans aren't the only ones who argue with their familial peers. Competition between siblings has been widely documented and studied among animals, birds, fish and insects. The rivalries are especially intense among some seabirds and predatory birds and sometimes end in siblicide.

5. Your parents lied: They do have a favorite.

You know how they always said they like you and your brothers and sister all the same? That's likely a white lie. A much-cited study found that about 70 percent of fathers and 65 percent of mothers admitted that they had a favorite child. For dads, it's usually the youngest girl. For moms, it's typically the oldest boy. Parents may choose their favorites, consciously or subconsciously, based on factors such as appearance, academic or athletic prowess, birth order or personality. Though they may not realize their bias, kids often do — which can add to the sibling rivalry within a household.

6. Siblings can be bad role models.

Kids with older siblings who drink are twice as likely to start drinking and those with older brothers or sisters who smoke are four times as likely to pick up the habit. Girls are four to six times more likely to become pregnant as a teen if they had an older, pregnant sister, says Patricia East, a developmental psychologist at the University of California, San Diego.

7. Siblings can cause — and help you deal with — stress.

Sure, they might tease you or steal your gum, but when the going gets tough, your siblings have your back. Especially if you're going through tough family times like parental arguments, they can relate and that understanding can help ease stress, says Judy Dunn, a professor of developmental psychology at King's College London.

Mary Jo DiLonardo covers a wide range of topics focused on nature, health, science and anything that helps make the world a better place.

7 reasons siblings are wonderful (and weird)
We have a unique relationship with our brothers and sisters, the people who help shape our lives.