You hear it from teachers, instructors, coaches and especially from experts on boys.
"Competition is natural."
Just because it's natural doesn't always make it acceptable. For example, I may naturally have some gray hair, but that don't mean it's right!
Competition among family members can be one of the most detrimental relational experiences. In competition, there is always a winner and a loser. Efforts to gain approval often lead to constant striving, winning at any cost and low self-esteem.
In competition, someone always feels left out, second best, last or undervalued. In families where the members experience these emotions, certain members will give up, give in and withdraw. It's difficult to be a strong family when one or more members are always striving to be the center of attention, or the "winner" if you will.
That said, competition is a great way for the family to bond. The natural competition occurs in trying to better the family as a whole. Setting goals, dreaming together and succeeding at family projects, strengthen family ties.
Those are the ties that bind.
Strong families play together, and win as a whole, so they'll stay together.