“You tickle the rat whiskers, and the human cells fire,” said Henry (Hank) Greely, a bioethicist at Stanford University. “There’s a lot of weird stuff here.”

In the past decade, human neural organoid research has been moving at a “break-neck pace,” Greely said, but it lacks the legal and ethical guidelines that should accompany a field that is, according to Greely, “peculiarly ethically sensitive.”

“If [neural organoids] were human, we’ve got Institutional Review Boards; if they were animals, we’ve got the Institutional Animal Care and Use Committee—but they’re neither,” Greely said. “There’s no regulatory setup that’s looking at the organoids as organoids.”