Induced pluripotent stem cells (iPSCs) have revolutionized regenerative medicine by enabling the reprogramming of adult somatic cells, such as skin cells, back to a stem cell state. Unlike ordinary skin cells, these induced stem cells regain the capacity not only to self-renew through duplication but also to differentiate into various specialized cell types, mirroring embryonic stem cells in functionality.

The dual capability of iPSCs to both duplicate and differentiate is essential for their applications. Duplication ensures that a stable pool of stem cells is maintained over time, avoiding the depletion of the stem cell reservoir. Simultaneously, differentiation allows the generation of diverse cell types required for tissue repair, disease modeling, and transplantation therapies.

This balance resembles natural stem cell behavior, where asymmetric division produces one daughter’s self-renewal to maintain stemness and the other’s differentiation to fulfill physiological demands. Induced stem cells, therefore, offer a renewable and versatile source of cells for laboratory studies and potential clinical applications.

Thus, the correct statement summarizing their function is:

(4) Differentiate and duplicate such that number of stem cells remains constant

Understanding this property underscores the therapeutic promise of iPSCs in personalized medicine, where patients’ own cells can be reprogrammed and harnessed for regenerating damaged tissues without immune rejection risks.

Answer: (4) Differentiate and duplicate such that number of stem cells remains constant