QWhere do stem cells come from?

AEmbryonic stem cells come from donated excess fertilized eggs created for the in vitro fertilization (IVF) process, tissue that would otherwise be discarded. Induced pluripotent stem cells are generated in a lab, often by manipulating “mature” cells (such as skin or blood cells) to an embryonic-like state through a process called “reprogramming.” Tissue stem cells are derived from their “home” tissue; for example, muscle stem cells from muscle tissue.