Tiny 'brains' grown in the lab could become conscious and feel pain — and we're not ready

An illustration of a brain in a jar.

Scientists are getting closer to growing human brains in the lab, and it's spurring an ethical debate over the welfare of these lab-reared tissues.

The debate surrounds "brain organoids," which are sometimes mistaken for sci-fi-inspired "brains in boxes." However, these small assemblies of brain tissue grown from stem cells are too simple to function like a real human brain. As such, scientists have assumed brain organoids lack consciousness, which has led to lax research regulations.