Organoids make it possible to study diseases that cannot be exhaustively studied in animals, such as uniquely human neuropsychiatric or neurodevelopmental diseases that affect the whole genome (schizophrenia, for example).16 Brain organoids are already being used in the study of neurodegenerative disorders such as Alzheimer's17 and neurological disorders such as epilepsy.18
Organoids also promise to help us understand previously opaque processes in early foetal development. Many chronic diseases emerge during the first weeks of development (for example, cardiovascular disease) so understanding these pathways in a more transparent way is crucial for prevention. Embryoids could also help us understand why humans carry fewer pregnancies successfully to term than other animals, which could lead to improved fertility enhancers and contraceptives.