Brain organoids have the broad molecular characteristics of normal human brain cells, but without some important details. They have a confused identity; a single organoid cell expresses multiple gene programs that are normally found in very different cell types. The human brain has a plethora of distinct cell types, but organoid cells express markers of multiple different neural types at once. Organoid cells also don’t mature like normal brain cells do. In addition, many of the features that are hallmarks of the developing human brain – like the structural expansion and increasing architectural complexity – are not reflected in the organoids.