It took millions of years for apes to evolve into humans. It may take only a century for humans to change again.
Genetic engineering, which for decades never quite lived up to its promise, is being transformed thanks to a new tool called Crispr. Scientists can use it to manipulate the genes of any living creature with astonishing ease. Its initial applications have been to target genetic disease, modify foods, and develop new drugs. What comes next is up to us.