Don’t let anyone call you a classic middle child. A new study of 377,000 high school students suggests that birth order doesn’t significantly impact personality or intelligence. Researchers found that though first-borns are indeed slightly more extroverted and a bit smarter on average, the difference is negligible, equating to just one IQ point. Theories of standardized sibling personality differences date back to Sigmund Freud’s time. But this research suggests that birth order — and sibling rivalry — should not influence parenting style.