Genetic diseases from cancer to congenital blindness could be cured, but CRISPR’s possibilities go far beyond that, from bioengineering crops to resurrecting extinct species (scientists at Harvard are working on the woolly mammoth) to the moral slippery slope of designing “better” humans.

Raised in rural Hawaii, Doudna says she was always drawn to understand the lush environment that surrounded her. “I was, and still am, fascinated by the natural world and humankind’s place in it,” Doudna says. Now she’s inadvertently gone from biochemist to public ethicist, traveling the world to talk about how CRISPR should be used and writing about our “unthinkable power to control evolution” in 2017’s A Crack in Creation. She recently led the condemnation of a Chinese scientist who skipped years of needed research and tests and clandestinely edited the embryos of twin girls, a practice banned in more than 40 countries.

“It made me think of horrible Nazi experiments,” says Doudna. “I felt that level of horror.” But she’s hopeful about CRISPR’s ultimate impact — its “ability to radically improve human health and the world we live in. The promise is truly that immense.”