What defines totipotent stem cells in terms of differentiation potential?

Totipotent stem cells are unique in their ability to differentiate into any cell type within an organism. This includes not only all of the cell types that make up the various tissues of an organism, such as muscle, nerve, and skin cells, but also the extraembryonic tissues such as the placenta. This remarkable capability allows them to give rise to a complete, living organism.

This distinguishes totipotent stem cells from pluripotent and multipotent stem cells, which have more limited differentiation potential. Pluripotent cells can develop into almost all cell types but not the extraembryonic tissues, while multipotent cells are restricted to a narrower range of cell types within a specific lineage or tissue type. Thus, the defining characteristic of totipotent stem cells is their unmatched versatility in forming any cell type necessary for developing a complete organism.