Despite his frantic backtracking, James Watson’s statement that Africans are less intelligent than Europeans follows a long and dubious tradition of geneticists claiming that supposed racial differences have a genetic basis. The idea goes back to the birth of the science of evolutionary genetics and its bastard sibling: eugenics.

After the death of his young daughter, Charles Darwin lamented natural selection’s “clumsy, wasteful, blundering and horribly cruel action”; but perhaps man could do better. Darwin did not suggest this step himself, but in the 1930s six of his family were members of the British Eugenics Society, and his son was president from 1911 to 1928. The Galton laboratory at the University of London is named after Darwin’s cousin, the geneticist Francis Galton, who coined the term eugenics and advocated perfecting the human race by breeding “those only of the best stock” so that the “feeble nations” could give way before the “nobler varieties of mankind”.

Eugenics societies sprang up at the beginning of the 20th century in most western countries to promote breeding programmes, but the movement was not confined to scientists. Browse through the Eugenics Society’s membership list and you find lords, ladies, bishops, academics, writers, doctors, artists and politicians from all sides. As a cabinet minister, the young Winston Churchill advocated compulsory sterilisation of “the feeble-minded and insane classes”. George Bernard Shaw and HG Wells were profoundly influenced by Darwin. The contraception pioneer Marie Stopes campaigned to pass laws to enable sterilisation of the “hopelessly rotten and racially diseased”.

Event today, geneticists are investigating the genetic basis of intelligence, creativity, sexuality and criminality. Recent controversial evidence that genes may indeed be linked to these traits has not come as a surprise to sociobiologists, such as Edward O Wilson, who have argued that mankind cannot escape its genetic inheritance. But the debate that must follow

has nothing to do with Watson’s remarks. Like his predecessors, Watson betrays fears and suspicions: this time of white privileged Americans of a world slipping beyond control.