Stem cells are probably going to be extremely useful.

Adult stem cells tend not to form tumors.

There are no bona fide treatments available for embryonic stem cells. There is nothing in the laboratory, and there is certainly nothing in the clinics available to patients.

Today, it is research with human embryonic stem cells and attempts to prepare cloned stem cells for research and medical therapies that are being disavowed as being ethically unacceptable.

I was working with stem cells as part of a NASA programme. We realised that the science of stem-cell proliferation was also fundamental to cancer cells when cancer enters the phase of metastasis.

Stem cells have the potential to be used to treat and better understand some of the world's most deadly and disabling diseases.