The stem cell controversy is the consideration of the ethics of research involving the development, usage, and destruction of human embryos. Most commonly, this controversy focuses on  embryonic stem cells. Not all stem cell research involves the creation, usage and destruction of human embryos. For example, adult stem cells, amniotic stem cells and induced pluripotent stem cells do not involve creating, using or destroying human embryos and thus are minimally, if at all, controversial. Many less controversial sources of acquiring stem cells include using cells from the umbilical cord, breast milk, and bone marrow.