"Embryonic stem cells have the ability to develop into virtually any cell in the body, and they may have the potential to treat medical conditions such as diabetes and Parkinson's disease. In August 2001, President Bush announced that for the first time federal funds would be used to support research on human embryonic stem cells, but funding would be limited to 'existing stem cell lines.' NIH [National Institute of Health] has established a registry listing the 78 human embryonic stem cell lines that are eligible for use in federally funded research, but only 22 cell lines are currently available. Scientists are concerned about the quality and longevity of these 22 stem cell lines. For a variety of reasons, many believe research advancement requires new embryonic stem cell lines, and for certain applications, stem cells derived from cloned embryos may offer the best hope for understanding and treating disease. However, an investigation by Seoul National University found that scientist Hwang Woo Suk had fabricated results on deriving patient-matched stem cells from cloned embryos - a major setback for the field. A significant cohort of pro-life advocates supports stem cell research; those opposed are concerned that stem cell isolation requires embryo destruction. Some have argued that stem cell research be limited to adult stem cells obtained from tissues such as bone marrow or umbilical cord blood. They argue that adult stem cells should be pursued instead of embryonic stem cells because they believe the derivation of stem cells from embryos is ethically unacceptable. Other scientists believe adult stem cells should not be the sole target of research because of important scientific and technical limitations. Some scientists are exploring the possibility of obtaining human embryonic stem cells that bypass the destruction of living human embryos. The President's Council on Bioethics cite four potential alternative sources of human embryonic stem cells in a May 2005 paper."
CRS Report for Congress, RL31015