STEM CELLS

Stem cells are generally characterised by the fact that they can be multiplied identically and  indefinitely, that they can give rise to a prolific amount of transition cells, originally from very different specific cells (nervous, muscular,  …).

Human embryonic stem cells

The preparation of human embryonic stem cells (ES, Embryo Stem Cells) involves the production of a human embryo and/or the use of surplus embryos from an IVF; a sample is taken from a premature embryo (at the blastocyst stage) which requires destroying the embryo. These embryonic stem cells are then cultivated in order to produce a very large quantity of identical cells. 

These cells mark the beginning of  the preparation of specific cells obtained by techniques that are still being fine tuned. These facts have shaken up the scientific, commercial and media worlds in allowing people to think that certain cloning techniques promise long-sought cures for terminally ill patients.   The information has, above all, shaken up the political world, in particular in the UK, Japan, Australia and the USA where there is huge pressure for federal funds to be used for human embryonic research.
The french law of 8th July 2004 recalls that "research on human embryo is forbidden", but authorizes it "exceptionally", for a 5-year time period, on surplus embryos without any parental project.

Adult Stem Cells

Studies on adult stem cells (ASC) have shown that  stem cells were present in many adult tissues but that they were considered not to be as versatile as the embryonic ones as they were  unable to develop into any type of cell.