Bush's limitation only applied to federal-funded research. State- and privately-funded researchers were free to create new embryonic stem cell lines and they did. However, one of the results of the federal limitation was funding for adult stem cell research that might have gone undone.
Well, here it is some eight years later and what do I read in US News Weekly, Feb. 27, 2009? "Why Embryonic Stem Cells are Obsolete" by Bernadine Healy, MD, cardiologist and a former head of the National Institutes of Health and the American Red Cross:
"... embryonic stem cells injected into patients can cause disabling if not deadly tumors. ... research in animals has shown repeatedly that sometimes the injected cells run wildly out of control—dashing hopes of tiny human embryos benignly spinning off stem cells to save grown-ups, without risk or concern."But, the news is not all bad, according to Healy:
"Even as the future of embryonic stem cells has dimmed, adult stem cell research has scored major wins evident just in the past few months. These advances involve human stem cells that are not derived from human embryos. In fact, adult stem cells, which occur in small quantities in organs throughout the body for natural growth and repair, have become stars despite great skepticism early on. Though a more difficult task, scientists have learned to coax them to mature into many cell types like brain and heart cells in the laboratory. (Such stem cells can be removed almost as easily as drawing a unit of blood, and they have been used successfully for years in bone marrow transplants.)"Best of all, adult stem cells exactly match the recipient, because they are his or her own cells.