Embryonic stem cells are the cells that exist in an early stage embryo. The ultimate embryonic stem cell is a fertilised egg – one cell that is capable of dividing to give rise to every one of the billions of different cells in the human body. The stem cells in an embryo are very special – not only can they develop into a new and unique human being, they have recently been shown to have many useful applications in modern medicine.
Perhaps not surprisingly, the use of embryonic stem cells is fraught with controversy. Many people feel that it is morally wrong to use human embryos just to harvest cells, no matter how they will be used. They believe that life starts at the moment of fertilisation and taking cells from an embryo can never be justified. Others take the view that as long as the research is tightly controlled, doctors should be allowed to use early stage embryos to provide the stem cells that could help people with cancer or Parkinson’s disease.
This article on embryonic stem cells is by Kathryn Senior, a freelance journalist who writes health, medical, biological, and pharmaceutical articles for national and international journals, newsletters and web sites.
How are embryonic stem cells obtained?
Embryonic stem cells for use in medicine and medical research are taken from very early stage embryos. These are embryos that have been created by in vitro fertilisation. During this process, quite a large number of ‘spare’ embryos are generated. The couple whose egg and sperm have been used are able to donate these spare embryos to medical research, which they do by giving their written consent. No embryos are created specifically for medical research.
The embryos used are about 5 days old and usually contain a hollow ball of cells. This is the blastocyst that eventually differentiates to form the baby and the placenta. The embryos used to obtain stem cells are never implanted into a woman’s body. They are created in the laboratory and are then used there. Individual cells are removed and then cultured in special conditions. Many of the cells don’t survive but some do and are used to create stable embryonic cell lines and can be cultured over a long period for research.