The key issue
Andrew Thornett has clearly identified the key issue in the abortion debate, namely 'What constitutes a human being?' as Scripture clearly forbids the killing of the same. When does a zygote or embryo become a human being and therefore assume the right not to be killed?
He argues that this must be at the point that the 'spirit' enters the body and from Old Testament references suggests that this must take place before birth. He then postulates six weeks as the time on the basis of the fact that the first blood cells are formed at this time, and that the Bible states that the life is in the blood.
When does life really begin?
Different transition points have been suggested by other authors. The more popular ones have been implantation (one week), neural crest stage (14 days), rudimentary circulation (21 days), breathing movements (12 wks), viability (approx 24 wks) and birth. The problem with most of these is that they are either difficult to define exactly in time, or occur at variable stages in gestation. As a result they may not give us a cut-off mark which is of any practical use in making decisions. For example, neural crest development, blood formation and circulation and breathing movements develop over a period of time. At what point in a continuous process do we draw the line? Viability is dependent on a multiplicity of factors including maturity at a given gestation, pharmacological intervention and the level of neonatal intensive care available. To take birth as the divider is ridiculous as Andrew points out. What qualitative difference is there between an infant one minute before and one minute after birth? Furthermore are we to say that a premature infant at 25 weeks gestation on a ventilator is a human being while a post-term infant of 42 weeks still in utero is not?
Where do we draw the line?
Human development is a continuous process beginning with fertilization. Essentially the only difference between a fertilized ovum and a full term baby is nutrition and time. The genetic code is present in full from the very beginning. A fertilized ovum is human certainly. It is not a cat or a snake or a cabbage - and certainly it is alive! It possesses at least in rudimentary form those attributes of a living thing - movement, respiration, sensitivity, growth, reproduction, excretion and nutrition. By virtue of being alive is it not then a 'being'? And by virtue of being a human is it not then a 'human being'? Not a 'potential' human being but rather a human being with potential, a potential fetus, infant or adult. Should it not then be accorded the rights that any human being has by virtue of being made in the image of God? At least at zygote or embryo stage it has not yet committed any capital offence.
What about the Spirit?
But I hear you saying, 'this is all very well but when does the spirit enter? - it is that which we do not know for sure and it is that which determines when a fertilized ovum becomes a human being with rights'. Is this a valid question? Some Christians have said that human beings can not be divided into body and spirit at all, that this is an ancient Greek idea which finds no support in the Bible. But is this really true? There must be something that survives death. What is it that is further clothed by a new resurrection body? What is it that faces judgment? What is the 'earthly tent' that Paul talks of? The Bible does support a spirit-body 'dualism' of some sort. So to ask when the spirit enters the body is a valid question. So when does it? We know from Scripture that God 'knows us' (which implies that we must be human beings in the sense of having rights) even 'before' he forms us and we have argued before that the formation of a human being is a continuous process beginning at conception. Is it not then quite possible that the zygote is a human being from the moment of fertilization? Or to put it another way - how can we be sure that the 'spirit' (if indeed it enters the developing human at all) does not enter at fertilization? This seems a very logical time, being the point at which human life begins. If we can't be sure that the spirit doesn't enter at the time of fertilization, then how can we be sure that by prescribing the 'morning after' pill or by inserting an intrauterine 'contraceptive'device (IUCD) we are not taking the life of a human being? It seems we must admit that at least there is a possibility that we are. Should we not then err on the side of caution?
But how can a zygote have a relationship with God?
But you object. How could a single celled zygote which contains no differentiated neurological tissue and is not even aware of its own existence be in any sort of relationship with God? If it is incapable of any relationship then how can it possess any personal status? This sounds like a good argument. But doesn't it misunderstand the whole concept of being made in the image of God? The status of the embryo is derived not from the fact that it knows God in any sense. Clearly it is incapable of this. Its status is derived from the fact that God knows it. Its dignity does not depend on its own personal attributes but is rather given to it by God.
But doesn't God himself terminate embryos?
Another argument for not regarding embryos as human beings is the fact that 40% to 70% of normal embryos are lost in their first month of life. This is a peculiar argument. One can not argue that personal status is somehow dependent on likelihood of survival. We would not dare argue for instance that because infant mortality is high in developing countries as a result of adverse environmental conditions or poor nutrition that we should therefore be justified in killing malnourished or deprived infants ourselves. Our usual response as doctors in this situation would be to find out why the mortality rate was so high and if possible to do something about it. If no intervention is practicable then we do not conclude that those who died were therefore not human beings. Nor can we argue that since God allows large numbers of embryos to die he himself therefore must not regard them as human beings. This is to put ourselves in the position of God and to presume that we know his purposes when he has not chosen to reveal them to us. Even if we are to say that God himself is the greatest terminator of embryos, this does not give us license to join him in the destruction. God may give and take life as he chooses. It is his sovereign right as God. It is not our right. We may only exercise those rights which he specifically delegates to us and destroying embryos is not one of them.
What about the embryo who was God incarnate?
We might ask at what stage the 'spirit' of Christ entered the embryo of God incarnate. If Christ was indeed conceived by the power of the Holy Spirit would it not be reasonable to assume that the Holy Spirit entered at conception?
Although I cannot demonstrate with certainty that the human embryo possesses a 'spirit', I have demonstrated that there is good enough reason to believe that it may. It follows therefore that we should refrain from deliberately destroying it.
What is the point of all this argument? The point is that as doctors we are not merely armchair theorists. We must make moral decisions and carry them out in the real world. By our practice we will set an example to those who follow. For our practice we will be accountable to God.
For these reasons I am unable to accept Andrew's conclusions. If we hold that the embryo does not become a human being until 4 to 6 weeks gestation - then we can have no real objection to destruction of embryos in vitro, experimentation with embryos, freezing of embryos, selling of embryos for profit, cloning of embryos, genetic engineering or selective destruction of embryos on genetic grounds. Pandora's Box has opened too far. It is far better to suffer the consequences of not fitting IUCDs than to be party to the destruction of what may well be the most innocent and defenceless form of human life there is. Although only the blueprint for an erythrocyte resides in the developing embryo, it is enough.