Embryonic stem cell research has more potential than adult stem cell research because embryonic stem cells can become any cell in the body, whereas adult stem cells can only become certain cells.

As far as I know the embryonic stem cells, being younger have a better chance of developing into what ever the researcher is making out of them. They are less developed and have a better ability to change. Adult Stem cells can change into what ever needed for the reseach, but you have less stem cells to work with because the adult body is developed. You have less stem cells to harvest and they are more mature.

Theoretically, embryonic stem cells have a greater potential to be manipulated into long-lasting cells of any type. A useful line of embryonic stem cells could be genetically altered so that they were not immunogentic in a host (would not be rejected even though they are foreign cells). Such a line could be used in every patient.

This would be preferable to getting adult stem cells from each patient and manipulating them for cell therapy. That’s an enourmous amount of work to do to treat one patient.

Theoretcially, adult stem cells might be able to manipulated so that a single line of cells could be used in many patients. Some progress has been made but it is slow going.

It would be good to compare adult stem cells to embryonic ones to see which were better to use. But research on embryonic stem cells has been crippled by legislation forbiding government funding. We are nearly a decade behind where we could have been on this research.