Cerebral organoids, also known as mini-brains, are tridimensional self-organized structures derived from stem cells that resemble the early stages of the human embryonic brain. This new tool allows researchers to explore fundamental neurodevelopmental steps otherwise inaccessible in utero experimentally. Alysson Muotri, UC San Diego Stem Cell Program, explains how mini brains are generated in his lab and how this strategy can create novel therapeutical insights on neurogenetic disorders, such as autism. He also describes the use of mini-brains to explore the uniqueness of the human brain compared to other extinct species, such as the Neanderthals. Limitations and ethical concerns surrounding this exciting technology will be discussed.