Dr. Andrew Laslett from the Human Embryonic Stem Cell Technology at the Australian Stem Cell Centre in Melbourne, who works with both IPS cells and embryonic stem cells, says the results have reinforced their work - he says though every new breakthrough in such adult stem cell technology inevitably evokes calls for work with human embryos to be abandoned, that action would be a mistake.

Dr. Laslett believes IPS cell technology still has a very long way to go for it to be considered safe and the only way to validate the IPS cells is to directly compare them to human embryonic technology.

In theory the research could mean that it is possible to clone someone using ordinary connective tissue cells found on the person's skin, but scientists say they are confident that their research will be used to understand the root causes of disease and lead to viable treatments and cures of human afflictions.

The research papers are published in the journals Nature and Cell Stem Cell.