Let’s Begin…

Shielded by our thick skulls and swaddled in layers of protective tissue, the human brain is extremely difficult to observe in action. Luckily, scientists can use brain organoids — pencil-eraser-sized masses of cells that function like human brains but aren’t part of an organism — to look closer. How do they do it? And is it ethical? Madeline Lancaster shares how to make a brain in a lab.