Adult vs Embryonic Stem Cell Research

There are two basic types of stem cells: embryonic and adult. Embryonic stem cells come from human embryos and form in the early days of human development before individual cells receive their "assignment"; for example, before they turn into blood, brain or hair cells. Some scientists speculate that these immature (or blank) cells can be coaxed into becoming any number of cell types, thereby holding great promise for healing the human body. However, harvesting these cells comes at a tremendous price: A living, human embryo must be destroyed.

Adult stem cells, on the other hand, come from a variety of sources, including the placenta, umbilical-cord blood, brain tissue, skin, bone marrow and body fat. Harvesting these cells requires no destruction of human life.   

There have been no successful embyronic stem cell treatments.