He Jiankui, an American-educated scientist based in Shenzhen, announced on Monday that he'd used Crispr, a powerful gene-editing tool, to make recently born twin girls resistant to HIV
There is no independent confirmation of He's claim, and it has not been published in a journal, where it would be vetted by other experts
Gene-editing could mean bigger harvests of crops with a wide array of desirable traits - better-tasting tomatoes, low-gluten wheat
The researchers have already used the method in the laboratory
Scientists have edited the pig genome to deactivate a virus that spreads to other cells