Romantic Bonding Theory
Once you realize that birth order can influence compatibility, a whole new way of seeing relationships opens up for you. Just as certain atoms have a natural affinity for one another and invariably attract to form stable molecules, certain people have a natural affinity and quickly form stable relationships when they meet.
In chemistry the power of atoms to combine is known as valence. Some people have much greater romantic valence than others. They've got the ability to make happy relationships with a more varied group of people. The lucky thing about being middleborn is that you have a greater romantic valence than any other birth order. Why should this be? It's because you can attract firstborns and lastborns, as well as other middleborns.
Your romantic valence, or compatibility potential, depends largely on the gender of your older and younger siblings and, to a lesser extent, on the age gap between you and them. For example, a girl with older and younger brothers is going to have tremendous romantic potential — she'll be compatible with virtually any guy who has a sister.
Put more simply, being middleborn is like having a secret charm working to make you attractive to almost everyone you meet. Not bad, huh?
We'll analyze the romantic compatibility of middle child Britney Spears to illustrate, briefly, how a knowledge of birth order could have helped her in her romantic life. Britney Spears has an older brother and a younger sister. The most important fact in considering romantic potential is opposite-sex siblings, especially those that are from one to five years apart in age. Her brother is four years older, her sister 10 years younger. So we can disregard her sister, who would have had a negligible impact on Britney's romantic potential. Her brother is the important factor, and since he's older her best match would be a firstborn boy with a younger sister. Keven Federline is a firstborn with two younger brothers, and would have been a relatively good match as far as rank conflict is concerned since a girl with an older brother usually gets along well with a firstborn male. But Kevin has sex conflict with her because he has no sisters and could be expected to have trouble understanding her. (Photo: Britney Spears.)