The late physicist suggested a new race of superhumans could develop from wealthy people editing their and their children’s DNA.
He wrote: “I am sure that during this century, people will discover how to modify both intelligence and instincts such as aggression.
“Laws will probably be passed against genetic engineering with humans.
“But some people won’t be able to resist the temptation to improve human characteristics, such as memory, resistance to disease and length of life.”
The author of A Brief History of Time also wrote that those who cannot afford these modifications, who he called “unimproved humans”, will eventually “die out” because they cannot compete with this new race.
He added: “Once such superhumans appear, there will be significant political problems with unimproved humans, who won’t be able to compete.
“Presumably, they will die out, or become unimportant. Instead, there will be a race of self-designing beings who are improving at an ever-increasing rate.”
The professor, who died in March, made the comments that refer to DNA-editing techniques such a Crispr-Cas9, which was invented six years ago.
The DNA-editing system allows for scientists to modify harmful genes or add new ones.
He made the predictions in a collection of articles and essays published in the The Sunday Times in preparation for a book that will be released on Tuesday titled Brief Answers to the Big Questions.
The professor spent his last years studying the so-called black hole “information paradox”.
The physicist’s work was finally completed just days before his death, aided by his colleagues at Cambridge and Harvard Universities.
The information paradox purports black holes have a temperature, which means they will eventually lose enough heat to disappear.
But under the laws of quantum mechanics, information is never lost, which appears to contradict the black hole model.
Professor Hawking and his associates have proposed objects sucked into a black hole will have their entropy changed – a law dictating the gradual decline or disorder of an object the hotter it is.