"Other scientists point out that our species is so young - Homo sapiens emerged from its African homeland only 100,000 years ago - that it simply has not had time to evolve any significant differences in intellectual capacity as its various groups of people have spread round the globe and settled in different regions. Only the most superficial differences - notably skin colour - separate the world's different population groupings. Underneath that skin, people are remarkably alike."

That sums things up pretty well - it comes from a report on all this in today's Observer -