By Andrew Dutney, Adelaide, Australia

1.Introduction
Stem cell research is not in itself particularly controversial. Everyone is touched in some way by one or more of the health crises that stem cell research hopes to address - spinal injury¹, Parkinson's, diabetes, heart disease and many more. The promise of new breakthroughs in the treatment of disease and injury using stem cells inclines almost all commentators to support the endeavour. Of course there are several important ethical issues involved that still need to be considered. - Is this development driven more by the desire for profit than concern for healthcare? How far should biotechnology industries be allowed to set the research agenda? Is Western culture no longer able to give people a sense of peace in facing the realities of aging and mortality? But it is generally agreed that the potential benefits justify the research effort.

The most intense ethical controversy around stem cell research has focused on one matter - where the stem cells are to be obtained. Children and adults have 'multipotent' stem cells that can be used in research and in experimental treatments. But the most versatile, 'pluripotent' stem cells are to be found in the human embryo at an early stage of its development. Adult stem cells can be helped to differentiate into many different kinds of cells but, theoretically, embryonic stem cells could be helped to differentiate into almost any kind of specialised cell. However, while adult stem cells can be collected without harming the person, embryonic stem cells are collected from the embryo by destroying it.

This is the focus of controversy in stem cell research - do the potential benefits justify destroying human embryos? Christian commentators have presented a range of views.

Roman Catholic teaching affirms that from the moment of fertilisation² the embryo's 'rights as a person must be recognised, among which in the first place is the inviolable³ right of every innocent human being to life'. Some Protestant commentators take the same position. In such a view, the deliberate destruction of an embryo is tantamount⁴ to murder or, if some version of the principle of double effect is applied, perhaps manslaughter.

By contrast, in the public discussion prior to and following the introduction of the Research Involving Human Embryos (Cth) Bill, in 2002, Anglican Archbishop Peter Carnley argued that the embryo should not be regarded as a human being until after 14 days of development. This is roughly the stage at which it develops the first signs of a primitive nervous system and also about the point at which the embryo would implant in the mother's uterus⁵ in natural conception⁶. It also brings to an end the period of time during which an embryo might split to produce identical twin embryos. This perspective has been conventional in public policy at least since the time of the Warnock Report in the United Kingdom (1984), which recommended that the cultivation of human embryos outside a woman's body should be limited to a period of less than fourteen days. Legislation in the United Kingdom and Australia has consistently adopted that restriction. In Carnley's view, then, 'conception' is a process that takes about fourteen days. For him, the destruction of the embryo in research can be justified up until that time.

My own view is like Carnley's, but different in one important respect. In my view it is not so much the developmental stage of the embryo that is crucial, but whether or not it has implanted in the woman's uterus. I hold that the 'conception' of a human being cannot be said to have taken place until (and unless) the woman becomes pregnant. In what follows I will provide a brief explanation of this position.

2. Fertilisation, implantation and conception
In natural conception several days may pass between the time when the woman's egg is fertilised and when it implants⁷ in the wall of her uterus and she becomes pregnant. In 'in vitro' fertilisation (IVF) the fertilised eggs are allowed to develop for some days before one or two of the healthiest embryos are transferred to the woman's uterus in the hope that one might implant in due course and she become pregnant.

The important point to note here is that there are two distinct stages. First, an egg is fertilised by a sperm (either naturally or by IVF), creating an embryo. Second, the embryo implants in the lining of the mother's uterus, having found its way to her uterus either naturally or by being placed there in an embryo transfer procedure (ET) after IVF. It is to be emphasised that in IVF-ET the clinician does not 'implant' the embryo in the mother's uterus, but 'transfers' it to her uterus from its petri dish⁸. Once transferred to her uterus the embryo either implants or it does not. Whether or not it implants depends on the condition of the woman's uterus and the condition of the embryo (especially, its chromosomal 'normality').

Implantation is a crucial process and one which is largely beyond the control of reproductive technology. It is something that happens in the interaction between the woman's body and the embryo. Clinicians estimate that a majority of embryos do not implant - neither in IVF-ET nor in unassisted conception. Indeed they have no prospect of implanting because of either their own morphology or because of the receptivity of the woman's uterus.

According to recent South Australian statistics, approximately 3.5 ET procedures are required to achieve one pregnancy. That is, since two embryos are generally included in each ET, approximately seven embryos are used to achieve one pregnancy. And this high rate of embryos failing to implant is considered by clinicians to be likely to compare favourably with the rate of failure in unassisted conception. In IVF-ET the embryologist has the opportunity to select the embryos which appear to be the best formed to be transferred; which ought to improve the implantation rate. In addition, the cycle of treatment includes the administration of drugs to optimise the condition of the woman's uterus and close monitoring of her cycle to ensure that the embryo transfer is conducted at the best time to achieve a pregnancy.

So while it is quite true that every human being began life as an embryo, it is not the case that every embryo is the beginning of a human being. Not even most embryos are the beginning of a human being - not in assisted reproductive technology, and certainly not in nature. Whether they are created naturally or through IVF, only a small minority of human embryos are in fact the beginning of human beings. Not until the woman is pregnant can we be confident that an embryo (or at least one of the embryos transferred in an IVF-ET procedure) is becoming a human being. And it is becoming a human being precisely by implanting in the mother's uterus. In that process, and not before, a human being is conceived.
1170 words
Source: Stem Cell Research and Cloning: Contemporary Challenges to Our Humanity, ATF Press, Adelaide, 2005, pp. 95-98


Annotations:
1. spinal injury - Wirbelsäulenverletzung
2. fertilisation - Befruchtung
3. inviolable - unantastbar
4. tantamount - gleichbedeutend mit
5. uterus - Gebärmutter
6. conception - Empfängnis
7. to implant - sich einnisten
8. petri dish - Petrischale (chem.)


Assignments:
1. What is the difference between embryo stem cells and adult stem cells?
2. What benefits could stem cell research have for ill people?
3. Under which circumstances would Christians allow research on embryonic stem cells?
4. What is the author's view on whether an embryo is a living being or not?
5. The majority of embryos do not implant in a woman's uterus and so are 'destroyed'. When do more embyos perish. in IVF or in unassisted/natural conception. Substantiate your findings.
6. Embryonic stem cell research could even result in cloning people which is commonly agreed as unethical. What is your opinion on cloning living creatures?

Stem Cell Research and Cloning: Contemporary Challenges to Our Humanity by Gareth Jones