Totipotent stem cells possess the remarkable ability to differentiate into any cell type, including those that form the placenta. In contrast, pluripotent stem cells can differentiate into virtually any type of body cell, but they lack the capacity to become placental cells.

Totipotent stem cells represent the earliest stage of stem cell development. They are found in the zygote and the initial few divisions following fertilization. These cells are unique in that they can develop into all cell types in the body, as well as the placental cells that are essential for supporting the developing embryo. Consequently, totipotent stem cells hold the potential to generate a complete organism.

On the other hand, pluripotent stem cells have a more limited differentiation potential. While they can give rise to any type of body cell, they cannot differentiate into placental cells. Pluripotent stem cells originate from the inner cell mass of the blastocyst, a hollow sphere of cells that forms several days post-fertilization. These cells are capable of generating all the various cell types in the body, excluding those of the placenta.

Both totipotent and pluripotent stem cells exhibit the ability to self-renew, which means they can divide and produce additional stem cells. This characteristic makes them invaluable for research and applications in regenerative medicine. However, the use of totipotent stem cells is often more contentious due to their potential to develop into a complete organism, raising significant ethical considerations.

In summary, totipotent stem cells can differentiate into any type of cell, including placental cells, while pluripotent stem cells can only differentiate into various body cells but not placental cells. Both types of stem cells are capable of self-renewal, which enhances their utility in scientific research and regenerative medicine.