The evolution of mankind has come to an end, because western countries lack older fathers. Professor Jones believes that fathers over 35 are more likely to pass on the mutated genes to the next generation. In a lecture entitled "Human evolution is over" held at University College London, he said that evolution consists of three parts: natural selection, mutation and random change. Professor Jones said: "It is very surprising that the mutation rate of our human beings has decreased due to the change of fertility pattern." Taking marriage style and contraception as examples, he said: "Social changes of human beings usually change our genetic future." Although chemical and radioactive pollution can also change genes, the most important mutation trigger is the delay of male reproductive age. This is because male cell division increases with age. He said: "Every cell division will increase the chances of mistakes, mutations and mistakes. The main childbearing age in western countries is 29 years old. As a father, sperm needs 300 cells to divide, while a 50-year-old man needs 1000 cells to divide during childbirth, and every division has a chance to make mistakes. Therefore, with the gradual decline of the number of children born by older men, the probability of mutation in human genes is also greatly reduced. In the past, a fertile man often had hundreds of children. " He took Moulay Ismail, the first monarch of the Moroccan Alawi dynasty, as an example. This man died in the18th century and gave birth to 888 children in his life. In this way, he sleeps with 1.2 women every day on average, and his fertility remains for 60 years.