Australian scientists have created a test to work out whether certain types of stem cells are unsafe.
The CSIRO has spent five years developing a safety test for induced pluripotent (iPS) stem cells.
iPS stem cells do not require a human embryo and are considered an important research advance.
Last month, scientists were able to .
There is much debate in the scientific community about the advantages of iPS stem cells over their embryonic counterparts.
The CSIRO's Andrew Laslett says there is still a number of question marks about the long term stability and safety of iPS cells.
"At this stage it appears that human embryonic stem cells may be slightly safer, but it's early days," he said.
Dr Laslett says the new test will provide more information about the quality of iPS and help identify unwanted cells that can mutate.
"Sometimes the cells that are made from the iPS cells change back into stem cells which are unwanted because these cells can form tumours called teratomas," he said.
Dr Laslett is hoping the research will be used to ensure stem cell therapies are safe for humans.
"Any cell line that's going to be used for cell therapy has to go through a whole barrage of different tests to see whether they're safe," he said.
"We hope that this one will be added to that number of tests... and it's really the first one that's entirely specific for human induced pluripotent stem cells."