Competition between siblings is often demonstrated by the statement, "That's not fair" or "What about him?" Competition stems from comparison and often creates conflict in relationships between brothers and sisters.
Here's an idea that will go a long way to reduce the comparison and competition between your children. Treat each child uniquely and don't try to treat all your kids the same. Intentionally give them different privileges, assignments, and responsibilities. Avoid grouping the children by saying things like, "Kids, it's time to eat" or "Boys, let's get in the car." Instead, use each child’s name and give separate instructions. "Bill, please wash your hands and come to dinner." "Karen, come join us now for dinner?"
When children compare themselves to each other they say they want equality, but that's not really true. What each child wants is to feel special. When you treat them uniquely, and focus on each child individually, you'll be surprised how much comparison and competition are reduced in your family.
After all, God doesn't treat us all the same. He treats us each uniquely. John 21:15-23 contains a fascinating story that often happens in families today. Jesus is telling Peter how he is going to die. Peter turns and looks at another disciple and says, "What about him?" Jesus answers, "What is that to you? You follow me." In essence Jesus was saying, "I treat each person uniquely. You worry about yourself." What a great lesson to apply to our families. Treat people uniquely and special instead of trying to treat them all equally or the same.