Bill Clinton is a first-born

They are serious and determined and are more likely to enter a profession, such as law or medicine.

Middle children are easy-going and gregarious, have more friends and have better people skills.

The youngest child, in contrast, is a charmer and manipulator who loves to get his own way.

The supposed differences are spelt out in a book by Michael Grose, a parenting expert in Australia.

Birth order

He maintains that birth order influences a child's personality.

His book 'Why first-borns rule the world and last-borns want to change it' points out that every US astronaut has been a first-born.

A child's position in his family impacts on his personality, his behaviour, his learning and ultimately his earning power Michael Grose

Similarly, he says more than half of all American presidents have been first-borns, as have most Nobel prize winners.

Certainly, many first borns have grown up to be powerful leaders. These include Winston Churchill, Saddam Hussein, Josef Stalin, Bill Clinton and George W Bush.

However, others have made it too despite the burden of having older siblings, not least Margaret Thatcher, Tony Blair and George Bush Senior.

Nevertheless, Mr Grose maintains that birth order is important.

"A child's position in his family impacts on his personality, his behaviour, his learning and ultimately his earning power," Mr Grose says on his website, Parenting Ideas.

"Most people have an intuitive knowledge that birth order somehow has an impact on development but they underestimate how far-reaching and just how significant that impact really is."

According to Mr Grose, only children have similar characteristics to first-borns.

"Research shows them to be more confident and articulate than other children, more likely to use their imagination and have healthy self esteem.

"Onlys expect a lot from others, hate criticism, can be inflexible and have difficulties sharing. They are also likely to be perfectionists like all first borns," he says.

Mr Grose believes parents should treat children differently depending on what order they have been born.

"First borns need encouragement as it releases them from the pressure on them to perform," he says.

"Seconds are often ignored or act up to be heard so they will respond to adults who are willing to listen to and take an interest in them," he says.

"Youngest borns are reminded every day that there is someone bigger, smarter and more capable than them so they often act the helpless role that others give them," he says.

"It is important that they learn to take responsibility."

And as for only children, the secret to brining them up well is to ensure they are not spoilt.

"As difficult as it is, make an effort not to spoil or over-indulge your only child. Treat your only child as if he or she was one of six children."