Dr Paul Irwing is a senior lecturer in organisational psychology at Manchester University. He claims that men are more intelligent than women.

All the research I've done points to a gender difference in general cognitive ability. There is a mean difference of about five IQ points. The further you go up the distribution the more and more skewed it becomes. There are twice as many men with an IQ of 120-plus as there are women, there are 30 times the number of men with an IQ of 170-plus as there are women.

I don't know why this is, all I can say is that we have a huge amount of data.

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In my 2005 paper in the British Journal of Psychology we looked at 22 surveys sampling 20,000 university students. In 21 out of the 22 studies males always had an advantage. That's a lot. We ignored the survey from Mexico because the results were consistent with a university that was extremely selective with respect to females. Why did Steve Blinkhorn call our research "flawed and suspect"?

The results of both studies were a shock to me. I find prejudice abhorrent. I've always taught sex differences from a left-wing point of view, that women are every bit as good as men. My findings don't fit my view of the world at all. Girls often do better than boys at school. There has to be some female compensating factor, most importantly the ability to process speech sounds, which means women read faster and more accurately and have an advantage in basic writing tasks. And women work harder than men and are more conscientious so they do things technic-ally correctly. Men are often quite original but deficient in what is technically demanded.

Historically women have been discriminated against. They've made tremendous progress and some people feel findings like this are a kick in the teeth. I have sympathy for that, but only people who know virtually nothing about IQ tests claim they have a cultural bias. All IQ tests are thoroughly tested and adjusted for bias, so if anything IQ tests are biased in favour of women not men.

People should have equal opportunities but if you want a society where everyone feels satisfied you're not going to find men and women doing the same things in the same proportions. It would help if we recognised that.