While some said his ideas could help save the planet, the astronomer royal and cosmologist Lord Martin Rees said the "modification of the genome is a remote, risky and dubious project", according to the Sunday Times.
In excerpts from his final book of essays - Brief Answers to the Big Questions, being published this week and billed as his last message to the world - Hawking warns genetic engineering may inevitably alter the trajectory of human evolution.
"We have now mapped DNA, which means we have read "the book of life", so we can start writing in corrections".
Hawking's predictions stem from gene-editing technology that already exists.
Hawking added that the emergence of a superior race will soon lead to implications for "unimproved humans" who he presumed will eventually "die out or become unimportant". "There is no time to wait for Darwinian evolution to make us more intelligent and better natured".
Hawking's suggestion has proven controversial among the science community.
The celebrated physicist suggested that genetic engineering would create a new race of humans that could destroy the rest of humanity.
Laws will be passed to keep genetic engineering under control, but "people won't be able to resist the temptation to improve human characteristics, such as memory, resistance to disease and length of life", he predicts, adding that such breakthroughs will likely happen this century-and be available only to the wealthy.
"Once such superhumans appear, there are going to be significant political problems with the unimproved humans, who won't be able to compete", he suggests. Instead there will be a race of self-designing beings who are improving at an ever-increasing rate'.
But in Hawking's view at least, superhumans are probably not the greatest threat humanity is staring down right now.