Birth order: Sorry, kid, first-borns really are smarter

Birth order makes a difference when it comes to brains, personality, study finds

Birth order within families has long sparked sibling rivalry, but it might also impact the child's personality and intelligence, a new study suggests. First-borns are typically smarter, while younger siblings get better grades and are more outgoing, the researchers say.

The findings weigh in on a long-standing debate: What effect if any does birth order have on a person's life? While numerous studies have been conducted, researchers have yet to draw any definitive conclusions.

The results lend support to some previous hypotheses — for instance, that the eldest sibling tends to have higher aptitude. But the study also contradicts other proposed ideas, for example, that first-borns tend to be more extroverted.