Researchers believe they have uncovered the reason why older siblings are more likely to earn higher incomes.

The debate over sibling birth order and its impact on success has long been a topic of interest, even causing rifts between notable figures like Sigmund Freud and Alfred Adler. However, regarding corporate success, the data is clear: older children tend to fare better.

https://fortune.com/2024/03/27/older-sibling-success-money-pay-career-nber-study