It is research that is guaranteed to delight men - and infuriate the women in their lives. A controversial new study has claimed that men really are more intelligent than women. The study - carried out by a man - concluded that men's IQs are almost four points higher than women's.
British-born researcher John Philippe Rushton, who previously created a furore by suggesting intelligence is influenced by race, says the finding could explain why so few women make it to the top in the workplace.
He claims the 'glass ceiling' phenomenon is probably due to inferior intelligence, rather than discrimination or lack of opportunity. The University of Western Ontario psychologist reached his conclusion after scrutinising the results of university aptitude tests taken by 100,000 students aged 17 and 18 of both sexes.
A focus on a factors such as the ability to quickly grasp a complex concept, verbal reasoning skills and creativity - some of they key ingredients of intelligence - revealed the male teenagers had IQs that were an average of 3.63 points higher. The average person has an IQ of around 100.
The findings, which held true for all classes and levels of parental education, overturn a 100 year consensus that men and women average the same in general mental ability. They also conflict with evidence that girls do better in school exams than boys.
But Prof Rushton, who was born in Bournemouth and obtained his doctorate in social psychology from the London School of Economics, argues that the faster maturing of girls leads to them outshining boys in the classroom.
And since almost all previous data showing an absence of difference between the sexes was gathered on schoolchildren, the gender difference could easily have been missed.
'It looks like up until late adolescence, the females have the advantage over males because they mature faster, which masks the underlying difference, he said.
Although experts have accepted that men and women differ mentally, with males averaging higher on tests of 'spatial ability' and females higher on verbal tests, it was assumed the differences averaged out, leaving no difference in overall intelligence.
Prof Rushton believes the differences are directly linked to brain size, with other studies showing men having slightly bigger brains than women.
'We know that men have larger brains, even when you take into account larger body size,' said the researcher. 'That means there are more neurons. The question is what these neurons are doing in a man - and they probably have an advantage in processing information.'
It is thought the difference may date back to the Stone Age, with women seeking out men who are more intelligent than them in a bid to pass on the best genes to their children.
'Some people have suggested it evolved because women prefer men who are more intelligent than they are for husbands,' said the professor.
'Just as they prefer men who are taller than them, they also prefer a male who is a little ahead of them in IQ.'
Critics claim Prof Rushton's results could have been skewed by the inclusion of more test results from females than form males.
Prof Rushton, who four years ago triggered a scientific row by claiming intelligence and behaviour are influenced by race, with blacks being more likely to be involved in crime and Asians having a greater chance of high IQs, however, stands by his results.
'These are unpopular conclusions,' he said. 'People should not be made to feel afraid to study controversial issues.
'We have the right to find the truth. One should really look at the facts.' His work appears to confirm British research which showed men have bigger brains and higher IQs than women, which may explain why chess grandmasters and geniuses are more likely to be male.
The analyses of more than 20,000 verbal reasoning tests taken by university students from around the world revealed that women's IQs are up to five points lower than men's .
Women needn't feel despondent, however, as the scientists believe women can achieve just as much as men - as long as they work harder.
