The ability of neuroscientists to create, grow and use human brain tissue in the lab is moving fast. So fast in fact that the journal Nature this week published a commentary signed by 17 neuroscientists, biologists and ethicists calling for an ethical framework for this endeavour.

The authors outline the three variants of such brain tissue: organoids, known as 3D “mini-brains” or “brain balls”, which are structures grown in the lab from pluripotent stem cells; ex vivo brain tissues, which are those removed from humans and kept …