All women and men may be created equal, but if you look at their bank accounts it will tell you that their incomes are not. The order in which siblings were born can not only have an effect on their personality but also impact their overall success in life, according to a new study from US organization the National Bureau of Economic Research.

First-borns are typically responsible and ambitious, the youngest are more entrepreneurial and have a bigger appetite for taking risks – and middle children are, well, stuck in the middle, says the study.

It used representative population data from Sweden to study how men’s birth order correlated with their occupations later in life. Data about personality traits was obtained from psychological assessments taken when the men enlisted in the Swedish military. The country had military conscription until 2010 and announced the policy’s reintroduction earlier this year.

Researchers from Sweden and the United States found that the first-born men interviewed were more emotionally stable, persistent, socially outgoing, willing to assume responsibility, and able to take initiative than those born later. But while first-borns are more likely to be managers, the researchers found that the youngest siblings are more like to be self-employed.

First-born (and only children) are natural-born leaders in terms of educational attainment, occupational prestige, income and net worth. Another distinction among the first-borns is that science Nobel Laureates are overwhelmingly in this category, as were 21 of the first 23 NASA astronauts to get into space. The other two were only children. 

Here’s a look at some famous first-borns: Zac Efron, Beyonce Knowles, Dakota Fanning, Harrison Ford, Matthew Perry, Jennifer Aniston, Angelina Jolie, Brad Pitt, Chuck Norris, Sylvester Stallone, Reese Witherspoon, and Ben Affleck.

Only children have similar characteristics to first-borns and are frequently burdened with high parental expectations. Research shows they are more confident, articulate and likely to use their imagination than other children. Because only children spend so much time alone, they tend to be self-entertainers and often tend to be the most creative members of a birth order. One researcher calls them “Super First Borns”. Like first-borns, they are confident, pay attention to detail, and tend to do well in school.

Some famous only children: Leonardo Da Vinci, Leonardo DiCaprio, Daniel Radcliffe, Natalie Portman, Elvis Presley, Alicia Keys, Russell Brand, Tiger Woods, and Maria Sharapova.

In his book “Born to Rebel,” psychologist Frank J. Sulloway argued that younger children are more likely to push against the family status quo. They tend to be the most creative and can be very charming and manipulative. 

Researchers at the University of Birmingham released a study last year showing that youngest children are 50 percent more likely to go into business than their older siblings if their parents were not already entrepreneurs. Overall, the youngest child tends to be the most creative and can be very charming – even manipulative, according to the Birmingham research.

Here are some famous last-borns: Jennifer Lawrence, Cameron Diaz, Harry Styles, Eddie Murphy, Stephen Colbert, Steve Carell, Ellen DeGeneres, and Whoopi Goldberg.

Sulloway stresses that these are just general trends – and that the whole birth-order theory can be turned on its head depending on the child's personality, the age gap between siblings and the family circumstances each child experiences during his or her formative years.