UNDER THE MICROSCOPE:There are biological reasons for extending the protection of the embryo back to the point of conception, writes William Reville.
THE ETHICAL IMPLICATIONS of human embryonic stem cell (HESC) research are currently the subject of vigorous debate, added to by yesterday's Irish Council for Bioethics report arguing that it should be permitted here in certain situations. I am prompted to return to this topic having viewed the Science Friction programme on HESC research, shown on March 4th on RTÉ1. I am opposed to HESC research on ethical grounds because it entails the deliberate destruction of embryos. My reasoning is based on biological facts.
The Science Friction programme was, in my opinion, unbalanced. Advocates of HESC research were allowed generous scope to advance optimistic projections of the
benefits of their approach, but this was insufficiently balanced by well-grounded counter-arguments. The recent recommendation of the Government-
appointed Commission on Assisted Human Reproduction to allow HESC research in Ireland was announced several times with no balancing mention of the minority dissenting report by Prof Gerry Whyte of TCD, arguing that the deliberate destruction of the human embryo is unethical.
Human life begins at conception when a sperm cell and an egg cell unite to form a zygote - the first embryonic stage. The embryo grows and develops. After several weeks it is called a foetus, which continues to grow and develop until born as a baby about nine months later. The baby grows and develops into an adult, who grows old and eventually dies. The whole process is a human continuum between the boundaries of conception and death, and is programmed to proceed automatically under normal circumstances.
Sometimes the early embryo divides into two identical halves, each of which develops to produce two identical twins. The history of each twin is a continuum exactly as described for the single-birth situation. Each stage along this continuum is fully human, having the full human properties and potential appropriate to its stage - zygote, foetus, baby, adolescent, adult and old person. All the genetic information in the human adult is already present in the single-celled zygote. Each point on this human continuum is dependent on the preceding part of the continuum and determines the succeeding part of the continuum. Interrupt the continuum at any point and nothing happens beyond that point. These are biological facts.
Accepting these facts, it seems to me to be wrong to arbitrarily pick any point on this continuum and claim that it marks the boundary between the preceding "not fully human and not deserving of protection" section and the succeeding "human enough to deserve protection" section. Obviously, my position on this is not universally accepted amongst scientists or the general public.
Our adult bodies contain over 200 major types of cells, all developed from the cells in the early embryo. These amazingly plastic embryonic cells are the human embryonic stem cells that are so desirable for HESC research simply because, if you had a stock of these cells and you knew how to manipulate and control them, you could generate any adult tissue you desired and you could replace any diseased organ with a new healthy organ. Therefore, research on stem cells holds out the prospect of developing cures for human diseases such as Parkinson's, Alzheimer's and so on.
But, unfortunately, in order to harvest the embryonic stem cells you must kill the embryo. I consider the embryo to be fully human, hence my ethical problem with HESC research.
It must be emphasised that we do not yet know how to control embryonic stem cells, so their medical usefulness remains to be proven. But, in any event, HESC research is no longer necessary from a scientific point of view. Its goals can probably be realised using stem cells derived from adult tissues, and there are no ethical problems associated with such research. Also, human skin cells have recently been dedifferentiated into stem cells that are just as useful as embryonic stem cells for medical research.
The potential of the microscopic embryonic stem cells to develop into a human adult is due to the amazing property they have peculiar to their position on the continuum of human life. It is because it is fully human that the embryonic stem cell is so desirable for scientific research. Advocates of HESC research camouflage this fact by referring to the early embryo as "only a microscopic ball of cells". But the biological fact is that the early embryo is "a human at his/her stage of a microscopic ball of cells".
In summary, biology demonstrates that the embryo sits on a fully-human continuum that develops automatically and extends from zygote to old age. Since any civilised philosophy must respect human life, we must respect the life of the embryo. The minimum level of respect we can show is not to deliberately kill the embryo.
William Reville is associate professor of biochemistry and public awareness of science officer at UCC. http://understandingscience.ucc.ie.