What primary characteristic defines stem cells?

Stem cells are defined primarily by their unique ability to develop into various cell types. This characteristic is crucial for their role in development, growth, and tissue repair in multicellular organisms. Stem cells are undifferentiated cells, which means they have not yet acquired a specific function or characteristic of a particular cell type. Due to their pluripotent or multipotent nature, they can differentiate into specialized cells such as muscle, nerve, or blood cells when signaled by the right conditions within the body.

This capacity for differentiation into multiple cell types is what makes them particularly valuable in both developmental biology and regenerative medicine, as researchers explore potential therapies for diseases and injuries by utilizing stem cells to regenerate damaged tissues or organs. Understanding this fundamental property helps clarify their applications in various biotechnological contexts, including cell therapy and tissue engineering.