What are other sources of stem cells besides human embryos?

Besides human embryos, stem cells can be sourced from adult tissues, such as bone marrow and adipose (fat) tissue, where they are known as adult or somatic stem cells. Additionally, induced pluripotent stem cells (iPSCs) can be created by reprogramming adult cells, such as skin or blood cells, to an embryonic-like state. Other sources include umbilical cord blood and placental tissues, both of which contain hematopoietic stem cells. These alternative sources provide valuable options for research and therapeutic applications without the ethical concerns associated with embryonic stem cells.