Family: Falling in Line

Since 1874, when Francis Galton declared that firstborn sons were overrepresented among scientists, researchers have demonstrated that birth order plays a role in everything from career choices to whom we marry. Here's a guide to perpetual family ties.

Firstborn

• Brains: Parents tend to pour their resources into the firstborn, ensuring that they have the best in life. Thus their IQ is 3 points higher than their siblings'.
• Family Ties: As the oldest, firstborns tend to act as surrogate parents to their siblings, taking on the role of family guardian. That makes them more likely to maintain family relations in adulthood.
• Competitive: Firstborns can be affected by the change of going from only child to older. The switch awakens the desire to maintain the position of favorite, causing them to be less trustful and more competitive throughout life.
• Conventional: Firstborns tend to be more conservative than their rebellious younger siblings. Radical political activists (think Trotsky and Castro) are 18 times more likely to be a laterborn than a firstborn.

Middleborn

• Careers: Literally being in the middle of things, middleborns tend to be unbiased and levelheaded, leading them to careers that involve negotiating. They are well-suited for positions in management and politics.
• Perfectionists: Having no defined role in the family, a middleborn plays the part of both older and younger sibling. They're less likely to be seen as a favorite child. In one study, mothers defined their middleborns as low in competence and achievement. Such a perception can reduce a child's self-esteem. Thus, middle-borns tend to be maladaptive perfectionists.
• Comrades: Middleborns are less likely to be involved with their families, reaching out to their peers and forming stronger relationships with individuals outside their kinship.

Lastborn

• Religion: Religious observance is stronger in first- and lastborns than middleborns. Religiosity (the importance of God in one's life) is highest in lastborns.
• Warmth: In families with three children, the lastborn is especially tender and altruistic, perhaps because he gets babied.
• Relationships: Research has shown that individuals are more likely to form romantic bonds with those who share their birth order. This may be because of similar personalities and life goals. Thus, lastborns are attracted to the babies of other families.