When the Brain Cells in the Petri Dish Stare Back

The Wall Street Journal | Essay

The proto-eyes are what really disturbed me.

For the past decade, medical researchers have been growing living, miniature replicas of parts of the human brain from stem cells. Such brain “organoids,” as they’re called, have always raised ethical questions. But when I learned that some of them had spontaneously developed optic vesicles—that is, precursors to eyes—I realized that the closer these experiments get to a real brain, the closer we get to creating sentient beings.