Scientists say they have created a stem cell line from a human embryo that had stopped developing naturally, and so was considered dead. Using such embryos might ease ethical concerns about creating such cells, they suggested.
One expert said the technique makes harvesting stem cells no more ethically troublesome than organ donation. But others said it still carries scientific and ethical problems.
The new work, published online by the journal Stem Cells, comes from Miodrag Stojkovic of the Prince Felipe Research Center in Valencia, Spain, with colleagues there and in England.
Dr Donald W Landry, director of the division of experimental therapeutics at the Columbia University Medical Center in New York, who proposed the idea of getting stem cells from arrested embryos in 2004, called the work an important addition to the field.
According to Dr Landry, taking live cells from dead embryos is like taking live organs from dead patients (which is ethical ).