An annual stem cell research conference in New York has been bringing together some of the field's top scientists to discuss breakthroughs in stem cell research and what proponents call its long-term application for curing major diseases. Victoria Cavaliere reports from VOA's New York Bureau that scientists say they have made great strides in the decade since the research began.

Stem cells are the body's master cells, acting as a source for the various cells and tissues in the body. Those taken from days-old embryos, called embryonic stem cells, are more malleable than stem cells from adults, and can transform into cells in every tissue and organ in the body.

Scientists want to use stem cells to find cures for such debilitating diseases as Parkinson's, cancer and diabetes.

The science of stem cells is at a fledgling stage, and stem cells have not yet been successfully used to treat or cure human disease.

But participants at the second annual New York Stem Cell Foundation Research Conference called the study of both adult and embryonic stem cells "robust" and "optimistic."

"We are learning about cell differentiation and the molecular basis of it. We are hoping eventually to be able to direct these stem cells with higher frequency into the cell types of interest that we want," said Dr. John Gearhart, a professor and leading researcher at the Johns Hopkins University Medical School.

Stem cell research, however, has sparked intense debate.

Critics condemn embryonic stem cell research as morally offensive because it leads to the destruction of human embryos.

In June, President Bush vetoed for the second time legislation to expand federally funded embryonic stem cell research. Congress has been unable to override his vetoes.

The Vatican supports stem cell research as long as it does not harm human embryos, which the Catholic Church says are human beings from the moment of conception.

Scientists at the conference say the possibilities for curing diseases through stem cell research are limitless. Dr. Douglas Melton, the co-director of Harvard University's Stem Cell Institute addressed another controversial issue, the concept of "cloning." He says there are no efforts to replicate people, just individual cells.

"I think this has been purposely confused in the debate of stem cell research. That is the use of somatic cell nuclear transfer, or cloning, to study degenerative disease. As far as I know, there is no credible scientist who has ever said he or she wants to clone people. In fact, the reason we want to do somatic cell nuclear transfer, or cloning, is because we want to make genetic copies of cells because it holds the possibility, perhaps for the first time, of studying complex degenerative diseases," he said.

Scientists point to a recent breakthrough in Britain, where researchers successfully implanted lung cells grown from embryonic stem cells into the lungs of mice. They say the cells successfully colonized and began growing into normal lung cells within two days. Scientists say this provides hope that such a method could eventually be used to repair damaged human lungs.