James Gallagher at the BBC:
Scientists in Japan showed stem cells can now be made quickly just by dipping blood cells into acid.
Stem cells can transform into any tissue and are already being trialled for healing the eye, heart and brain.
The latest development, published in the journal Nature, could make the technology cheaper, faster and safer.
The human body is built of cells with a specific role – nerve cells, liver cells, muscle cells – and that role is fixed.
However, stem cells can become any other type of cell, and they have become a major field of research in medicine for their potential to regenerate the body.
Embryos are one, ethically charged, source of stem cells. Nobel prize winning research also showed that skin cells could be “genetically reprogrammed” to become stem cells (termed induced pluripotent stem cells).