Ethics Associated with the Use of Embryonic Stem ...

Ethics Associated with the Use of Embryonic Stem Cells for Human Medical Therapy
Abstract
Therapeutic cloning of human embryonic stem cells raises several ethical issues debated by the public and scientists alike. Research is permitted in many countries on early embryos up to 14 days in order to obtain embryonic stem cells as it is argued the early embryo does not have the same rights to life as a born child and that an embryo created by therapeutic cloning may not even have the potential to develop into a child. International legislation governing research with these embryos needs standardising to further research and prevent misuse of this technology. The use of excess embryos from IVF procedures is justified and the case for allowing couples who donate oocytes to stem cell research to be compensated is presented. Alternative methods for obtaining stem cells would be preferable for researchers and donors if they can be developed.
Introduction
Deriving stem cells from humans was first anticipated in 1981 when Evans and Kaufman successfully extracted mice blastocyst cells and discovered their pluripotency (potential of undeveloped cells to differentiate into a number of types of body cell). However, human stem cell lines were not derived until 1998 by Thompson et al. This work brought with it huge potential for future medical therapy and understanding of genetic development and disease (Bjuresten and Hovatta, 2003). However use of human embryos in research also introduces the controversy of the ‘slippery slope’ notion that allowing use of embryos, foetuses or egg cells brings us closer to accepting human cloning. It also raises issues of who donates these cells, what use the cells are put to, how long they are kept and what happens to them after their use in research.
Stem cells may be characterised by their undifferentiated state, their ability to self renew and potential to differentiate into a specialised cell (Whittaker, 2007). There are two types; embryonic stem cells (ESCs) and non-embryonic stem cells. A fertilised zygote initially develops into a blastocyst, made up of the trophoblast and inner cell mass (ICM), see figure 1. The first four cells of the zygote are totipotent, meaning they have the potential to develop into any cell in the body under certain conditions. After this, during the blastocyst stage, cells of the ICM can be isolated in culture without loss of differentiation potential and so can develop into an embryo or ESCs that can be ‘programmed’ to be pluripotent. This gives them great therapeutic promise as they can be developed in cell culture into particular cell lines and may be used in tissue replacement or to research genetic diseases (Whittaker, 2007 and Condic, 2008).

Figure 1: Diagram of the blastocyst showing the trophoblast and pluripotent ICM cells. www.utm.utoronto.ca
Non-ESCs are also known as adult stem cells and have been used in some clinical ...