Growing up with a sibling will give you a unique slant on life. Besides having a constant companion, a natural born confidante, your sibling may prove to be your biggest rival. An extreme example of this behavior, would be what movie goers witnessed in the Boleyn Girls. The siblings in this film are not the norm, but sibling rivalry, particularly the adolescent type, can be tough to overcome in later years. To heal old wounds and become friends again you have to employ some new relationship skills.