“Is it true blondes have more fun?” asked the famous Clairol ad in the 1950s.
Queensland researchers may not be able to answer that question but they have discovered that fair-haired women have more cash.
Women with golden tresses have long been the brunt of jokes that portray them as clueless, ditsy or downright dumb.
But a recent study from the Queensland University of Technology shows blondes earn 7 per cent more than women with other hair colours.
The survey of 13,000 women showed that the difference in pay was not connected with other factors such as height, weight or education.
The study, published in the journal Economics Letters, also found that blondes tended to marry men who earned an average of 6 per cent more than other women’s husbands.
Dr David Johnston, who led the study, said the researchers could not show why fair-haired women earned more than their non-blonde counterparts, but no other hair colour showed such a trend.
“Blonde women are often depicted as being more attractive than other women, but also less intelligent,” he said.
“But it seems the association between blondes and beauty dominates any perception that they have low intelligence.
“This could explain why the ‘blondeness effect’ is evident in the marriage market.”
The president of the International Blondes Association, Olga Uskova, says “blondes really rule the world today”.
“People admire, envy, and make jokes about us, but nobody remains indifferent,” she says on the association’s website.
“[Being blonde] is not only a golden colour of hair, this is a state of mind, lifestyle and philosophy.
“Blondes can also be presidents, ministers, diplomats, business ladies.”
United States secretary of state Hillary Clinton appears to be one example of such a blonde and Australian Governor-General Quentin Bryce is another.
Blonde Westpac boss Gail Kelly came in at number 18 on Forbes magazine’s 2009 list of the world’s most powerful women – the highest-ranking Australian woman.
And fair-haired German chancellor Angela Merkel topped that list.
A skim through the profiles of female MPs in the House of Representatives reveals that more than half are blondes and most of those are bottle blondes.
Dr Ian Ward from the University of Queensland’s School of Political Science says most female politicians will have been advised to pay careful attention to their appearance, and that may account for their choice of hair colour.
But one notable exception from the blonde politicians is redhead Deputy Prime Minister Julia Gillard.
Dr Ward says it is possible Ms Gillard’s hair colour has been used to portray her as feisty and strong-willed.
“I’m sure somewhere in the Labor Party someone’s done a focus group and asked that precise question,” he said.
So if blondes earn more money and redheads can climb to positions of power, where does that leave dark-haired women?
It leaves them married to billionaires, according to a 2008 study by American internet company Lycos, which runs dating websites.
The study found that 78 of the world’s top 100 billionaires had wives or long-term girlfriends with either brunette or raven hair.