There is the ability to praise and correct without the audience( and it having any meaning) for the other children. It's a freer relationship and one in which bonding and closeness can be developed without interference.

Jonathan Caspi

Sibling relationships are so important, but they are often overlooked, if you feel like you are grounded and connected to your family of origin, they are like your home base. You've got these people you can always come back to.

The difference may be how severe the physical violence gets. Boys tend to do more damage, particularly when older, it was also assumed that girls relied more on relational aggression( e.g., strategies to socially humiliate, isolating, injure reputation) than boys. However, there is evidence that brothers use this approach about the same too.

When children complain about fairness, parents often dismiss it... which only confirms the sense that they are on the outside in the parent-children relationship. Acknowledge the feelings and openly discuss it, parents should observe how they intervene in sibling conflicts. Are Jonathan Caspi taking one's side more than the other's ? If so, change it up.