Embryonic Stem Cells

Human embryo growing inside a body

As their name suggests, embryonic stem cells come from living, human embryos. They are harvested from two sources.

• Embryos—Embryonic stem cells are obtained by harvesting living embryos which are generally 5-7 days old. The removal of embryonic stem cells invariably results in the destruction of the embryo.

• Fetuses—Another kind of stem cell called an embryonic germ cell can be obtained from either miscarriages or aborted fetuses.