However, "the destruction of even one human life can never be justified in terms of the benefit that it might conceivably bring to another," he said.
The Pontifical Council for Culture partnered with NeoStem Inc., a U.S. company researching and marketing adult stem-cell therapies, to sponsor the conference, "Adult Stem Cells: Science and the Future of Man and Culture."
The 30 speakers, along with patients who had been treated with stem cells, looked not only at the scientific progress being made with adult stem cells, but also at the cultural, ethical and political issues surrounding the research, its use and its availability.
Pope Benedict told conference participants that "in drawing attention to the needs of the defenseless, the church thinks not only of the unborn, but also of those without easy access to expensive medical treatment."
"Illness is no respecter of persons, and justice demands that every effort be made to place the fruits of scientific research at the disposal of all who stand to benefit from them, irrespective of their means," he said.
The Pope said the church supports research with adult stem cells, which have the possibility of developing into a variety of specialized cells and can alleviate degenerative illnesses by repairing damaged tissues.
Adult stem cells are obtained not from fertilizing and destroying human embryos, but from "the tissues of an adult organism, from the blood of the umbilical cord at the moment of birth or from fetuses who have died of natural causes," he said.
By calling for respect for the ethical limits of biomedical research, the Pope said, the church does not seek "to impede scientific progress, but on the contrary to guide it in a direction that is truly fruitful and beneficial to humanity."