Women with blonde hair have the competitive edge, being more aggressive and determined than redheads and brunettes, say scientists.

Fair-haired women, whether natural or out of a bottle, display a warlike streak when fighting battles to get their own way, findings suggest.

The Proceedings of the National Academy of Sciences work might explain why many leading women are blonde.

The University of California team studied 156 female students.

Blonde ambition

They found blondes were used to getting more attention and being treated better by others.

The researchers believe this sense of entitlement is what makes them more willing to "go to war" over an issue.

Lead researcher Aaron Sell said: "We expected blondes to feel more entitled than other young women - this is southern California, the natural habitat of the privileged blonde.

"What we did not expect to find was how much more warlike they are than their peers on campus."

His research found that the more "special" a woman felt, typically the blondes, the more likely they were to get angry to reach social goals.

Even those who dyed their hair blonde took on a natural blonde's attributes.

However, the blondes were less likely than brunettes or redheads to get into a fight themselves - possibly to ensure they preserved their looks.

'Princess' effect

Dr Sell said he suspected that blondes existed in a "bubble", where they had been treated better than other people for so long they did not realise that men, in particular, were more deferential towards them than other women.

"They may not even realise they are treated like a princess," he said.

Scientists say there is some suggestion that men are naturally drawn to women with fairer hair.

Cavemen are said to have preferred blonde mates because fair hair was an indication of higher levels of oestrogen and fertility.

But while being blonde might boost your social life, it could damage your career prospects, say other researchers.

A recent study found blonde females earned far less, on average, than darker-haired women.

Consultant psychologist Ingrid Collins of The London Medical Centre said the latest findings were interesting but should be interpreted with caution.

"People do tend to buy into and live up to stereotypes.

"But this is a small study on a very limited sample group so it is not possible to generalise."

I think what IS true is that the modern woman/girl in general has become more aggressive