Competing for the football, competing for better grades, or maybe even just fighting over the bathroom mirror are all things you may have experienced as a kid.
Trying to outdo your brother or sister may sound like child's play, but sibling rivalry can play a role at any stage in life. The good news is that there may be a benefit from all the bickering.
At 21 months, twins Cornelia and Jillian are two of a kind.
"It's monkey-see, monkey-do. It's exactly monkey-see, monkey-do," said mom Claudette Haney.
One climbs the playground, then the other is right behind. Is it an early sign of sibling rivalry? Mom thinks so.
"I feel like the rivalry probably comes from a struggle for attention."
If you fast-forward thru the life of the Garcia family, you'll see their three boys Jake, Tyler and Wesley know a thing or two about sibling competition on the field.
"One is usually following the other to get up to speed on what sport they like," said their mother, Kristin Garcia.
"It just depends who wants it more that day in whatever they're doing," offered their dad, Ignacio Garcia.
You don't have to be a twin for sibling rivalry to rear its head in almost every family. Researchers at Texas Tech University used a realistic baby doll to prove that children show signs of jealousy even at the youngest age.
"Most of the time when they do give you a response, it is very authentic. And the mother's responses to the kids is also very authentic. And the dilemma of how do I deal with two kids, not one at the expense of the other, but both of them, is such a compelling question," said Dr. Sybil Hart.
It may be compelling, but it's not so bad if you ask the Wilson brothers.
"It was a healthy, kind of competitive rivalry," said Paul Wilson.
The boys duked it out as kids, not only when they got boxing gloves for Christmas, but in sports and school.
"We had commonalities of football and riding a bike," Paul said,
Common interests created competition.
"Somebody would come home and make the football team. I was big enough, tall enough, strong enough to make the team so I would see that and all of those things would push me, drove me to be a little bit better athletically, to be a little bit better in school," Mark said.
The duo still pushes each other. This time on stage in their band. They are brothers in life and in music, along with their other, youngest, brother Patrick.
They are all grown up, but driving each other to succeed.
"I find myself watching him going, I just hope I can be that much funny as he is good. Or that much entertaining or that musical to match what he's doing," continued Paul.
Mutual admiration is a byproduct of sibling rivalry and the Garcia family is prepared to accept it.
Just ask Jake Garcia about his brother.
"I'm, like, proud of him. It makes me play hard. It makes me want to play harder," he said.
Much love in what just appears to be a war of dominance.
Just when is sibling rivalry a problem? Experts suggest for parents don't play favorites and avoid labeling one child as "the smart one" or "the creative one."