First-born daughters don't rule the world. Here's proof.

First-born girls are the mistresses of the universe.

At least, that’s what a new study about birth order, which found that first-born females were 13 per cent more ambitious than first-born boys, would have us believe.

The study of 1,503 family groups, conducted by the University of Essex’s Institute for Social and Economic Research in the UK, also found that first-borns in general were 16 per cent more likely to go on for higher education than their younger siblings. The only time that siblings of different ages were equally likely to go on for higher education was if there was a four-year gap between them, the study found.

Hillary Clinton, Oprah Winfrey, JK Rowling and Beyonce are all the oldest in the family – apparently suggesting that, as Queen Bey herself once declared, (first-born) girls really do rule the world. But what about other women we look up to closer to home?

We asked six inspirational Aussie public figures about how their place in the family has affected them — and the results are far from uniform.

Clare Bowditch. Singer, actor and founder of Big Hearted Business: Youngest of five.

Clare Bowditch

“I’m the youngest of five and probably the most ambitious of all of my siblings! They’re all really creative; I’m just the only freak who decided to go ‘semi-Pro’. I suspect that part of my ambition actually stems from wanting to make them proud and to give them something to cheer about, in a way!”

Chrissie Swan, radio and television personality: Youngest of three.

Chrissie Swan

“I think as the youngest I was able to take more risks. The rules get more relaxed as you go down the birth order and I think that’s great for creative types like me. Less rules = more creativity. Even though I have a wonderful career and personal life, I do not identify as ‘ambitious’. I was always having too much fun to have goals. Fun is high on my list of priorities, financial and professional success less so but the great irony is it seems I have achieved both of those things via a rigorous pursuit of fun and risk-taking. My sisters are seven and 10 years older than me so I had wonderful female role models very close by and they treated me as an equal, so I was batting above my average socially from the get-go. This has helped too.”

Juliette Wright, CEO/Founder of GIVIT: Only child.

Juliette Wright

“I am the only child and I am sure that has made me very independent. I love to be alone as much in the thick of a party. I am a very high-achiever, sometimes to my detriment… I have two kids under seven, I’m the CEO of an NGO and I work looong hours as a volunteer for my cause. I’m sure my only-child situation makes me a little immune to the nay-sayers that state I cannot achieve my goal.”

Elizabeth Broderick, Sex Discrimination Commissioner: Twin.

“I am an identical twin and it wasn’t until my twin sister went to get her birth certificate to

Sex Discrimination Commissioner Elizabeth Broderick

get a passport that we finally knew. Beside her name were the words “first-born”! Of course, I’d always suspected this because she was the bossy one! How has my birth order affected my success? I think growing up assuming that both my twin sister and I were first-born (as impossible as that is) and not knowing until later in life, probably meant that we are both quite achievement-oriented. After all, there is only five mins difference in age! A healthy rivalry existed between us – we both wanted to succeed – but my parents were determined that competition wouldn’t negatively impact on our relationship. My twin sister is now a professor of Medicine at Sydney University so she has succeeded at a high-level.”

Kim Wilkins, popular fiction author: Youngest of two.

Kim Wilkins

“I’m second of two (I have an older brother). I think it made me more independent and there were fewer expectations on me so I could make my own path.”

Karni Liddell, Paralympic swimmer, speaker, counsellor and disability activist: First-born.

Karni Liddell

“I’m first-born, I have a brother who is three years younger and I believe that I’m more family focused and I always put my family first and consider them in most of my decision-making processes; this could also be due to the fact that I have a disability.”

Jean Madden, founder of charity Street Swags: Second of seven.

Jean Madden

“I am the second child of seven. However, growing up I carried a great deal more responsibility for my other siblings than my older sister did. When I was 17, most of my family got very sick and my older sister left. I was the one who was looking after babies, making lunches and getting kids to school, whilst getting myself to uni. I have a very close relationship with all my siblings.”

Emma Isaacs, CEO of Business Chicks: Eldest of three.

Emma Isaacs

“I’m the eldest child in a family of three kids. I’ve always felt that being the first is a factor in who I’ve become as an entrepreneur. I had to learn to take risks early, do things on my own, not rely on anyone else and ultimately, make things up as I went along.”

Whether or not you’re first-born (or believe the research), here are some successful first-born individuals for your inspiration.

Does your family support the theory? Do you agree that birth order and age gap make a difference to personality?