Have we ceased to evolve?

According to one geneticist, the human rate of evolution is slowing down.

Although chemicals and radioactive pollution could alter genetics, one of the most important mutation triggers is advanced age in men.

This is because cell divisions in males increase with age.

"Every time there is a cell division, there is a chance of a mistake, a mutation, an error," he said. "For a 29-year old father [the mean age of reproduction in the West] there are around 300 divisions between the sperm that made him and the one he passes on — each one with an opportunity to make mistakes.

"For a 50-year-old father, the figure is well over a thousand. A drop in the number of older fathers will thus have a major effect on the rate of mutation."