We all have a clear idea of what an embryo is. Or do we?

The report from the Permanent Committee of Social Affairs. (July 2005) states that the embryo results at the moment when the process of fertilisation of the ova is completed... forming a new human cell which has the potential of individual development. This implies that without a human ovum and sperm there can be no embryo formation.

The significance of clear enunciation and definition of an embryo becomes crucial in defining how it may be treated. In contrast to practice in some countries like the UK, Malta supports the Council of Europe decision that no embryos should be created specifically for research purposes. This is the result of the presumed dignity inherent in the human embryo which would be challenged when embryos are destroyed for research purposes.

Over the past decade, stem cells from embryos achieved considerable notoriety as the best source of material with a great potential for the treatment of a number of degenerative disorders like Parkinson's disease, myocardial infarction, or diabetes. Other sources, like adult bone marrow or blood from the placenta have also been used but found less satisfactory for this purpose. Hence the dilemma faced by scientists working in this area: either follow the stream and use embryo stem cells or fall behind in the race for lucrative new modalities of therapy.

Innovative as usual, scientists have in recent years come up with other alternatives to human embryo-derived stem cells. In one instance, ova from rabbits or cows were fertilised by human DNA (not specifically a sperm) to produce a 'cybrid'. A clone of cells results which grows and multiplies and produces products (proteins) which are typically human (because they produced under the direction of human DNA). Such a clone is human by anything except name. Its genetic material is almost totally ("99.9 per cent") human. Such mixing of human and other species is forbidden by the Council of Europe Convention, but is nonetheless being resorted to as a way to circumvent the lack of human embryos for this purpose. It certainly does not fall within the definition provided by the report, since no human ova are involved in the process.

Other hopeful news has come from the Massachusetts company Advanced Cell Technology (ACT) claiming to produce stem cells "without interfering with the embryo's potential for life". They claimed that they could extract stem cells from a single cell taken from a developing embryo which has reached the eight-cell stage without actually harming it. This, if confirmed, would remove the main objection to embryo research, namely that it involves destruction. It, however, begs the question: what is an embryo? The cell taken at such an early stage of embryo development is itself capable of developing into an embryo, and has all the characteristics of an embryo cell. If placed in the right environment, it can develop into an embryo.

The most recent and promising information is contained in research from Japan by Shinya Yamanaka and his colleagues who have produced stem cells purely from adult human cells - without the need to use embryos, ova or sperm. They call these "induced pluripotent stem" (iPS) cells. Prof. Ian Wilmut, the creator of Dolly the cloned sheep, is so impressed with this that he has abandoned the original technique for this one. This technology has received the green light from such bodies like the Australasian Bioethics Information clearinghouse which commented that this could be "one of the great dreams of regenerative medicine".

So here is a cell which is human, because it is derived from human (albeit non-reproductive) tissue, which can be made to revert to its embryonic form, capable of multiplying and presumably differentiating into the various organs in the same way that an embryo can. If put in the right environment, such as a uterus, it might conceivably continue to grow into a foetus and embryo. The only difference would be that it was not the result of fusion of ovum and sperm but developed from stimulation of a normally non-reproductive cell. Is this a human embryo?

While scientists are desperately trying to avoid the embryo trap and use all sorts of imagination to bypass the use of human embryos as normally understood, they are in the process of producing chimeras, mixtures of human and animal cells, new ways of making normal human tissue revert to embryonic form and take on novel characteristics not expected in the course of normal development. While of necessity, ethical and, in particular, legal issues lag behind scientific advances, and it behoves us all to keep an open mind about these advances.

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