How should Christians respond?
BIOLOGICAL science crossed a significant milestone at 5 pm on July 5, 1996 when embryologists Drs Ian Wilmut and K. H. S. Campbell and their team at Roslin Institute, a research centre near Edinburgh, successfully cloned a lamb from cells taken from a mature sheep.
The technique they used is known as somatic cell nuclear transfer, which is illustrated at bottom.
Research into the medical potential of stem cells dates back to the 1960s, but it was not until November 1998 when the first human embryonic stem cells were isolated and cultured, that the public began to be excited at the possible revolutionary breakthroughs offered by stem cell research.
Stem cells are primitive or precursor and versatile cells in the body that can reproduce themselves and produce specialised cells. There are different types of stem cells in the body, and though they are all capable of developing into multiple tissues types or organs, not all of them share the same developmental plasticity. Scientists rank them on a scale of specialisation:
Totipotent stem cells are capable of forming every type of body cell and have the capacity to give rise to a fully-functioning organism. All cells within an early embryo up to the 16-cell stage are totipotent; each has the capacity to develop into a human being.
Pluripotent stem cells can develop into any tissue type such as bone, muscle, blood, and the nervous system, but not into a fully-functioning organism. Because they are more differentiated, pluripotent stem cells cannot develop into a human person.
Multipotent or tissue specific stem cells are limited in the types of tissues or cell lines they can develop into.
There are three main sources for stem cells: embryonic stem cells derived from the inner cell mass of very early embryos; embryonic germ cells obtained from foetal tissue at a later stage of development; and adult stem cells from mature tissues.
Of these, embryonic stem cells have the greatest flexibility in that they are pluripotent and can specialise into any type of cell in the body. Embryonic stem cells can replicate indefinitely in culture without undergoing change in their basic genetic make-up; they are thus virtually “immortal”.
[The] third source [of embryonic stem cells] is from embryos created by somatic cell nuclear transfer or cloning. It is here that the issues of human cloning and stem cell research impinge on each other. In therapeutic cloning, one is able to get made-to-order stem cells by deliberately creating embryos as sources for stem cells; something, for instance, the Jones Institute in Virginia — where the first US test-tube baby was produced — has indicated it will do.
With further refinement in the science of therapeutic cloning, it may be possible to obtain embryonic stem cells from a parent embryo bearing the genetic make-up of the person in need of transplantation. This will hopefully lead to the generation of autologous stem cells (cells which are genetically specific for a given individual) which will overcome the problems of organ rejection, and the resulting need for immuno-suppressant drugs in transplant patients.
Despite the many medical benefits promised by stem cell research, it remains a contentious issue, mainly with regards to the moral status of the human embryo. Since obtaining embryonic stem cells necessarily entails the destruction of embryos, this raises the ethical question as to the morality of such research.
If the embryo is a human life and contains within it all the development potential of a human person, would not the harvesting of stem cell be tantamount to destroying life? The question as to what constitutes human life and dignity is one that is pertinent to both human cloning and experimentation on embryos. How should the Christian community respond to these developments?
This is an extract from the book “A Christian Response to the Life Sciences” which is a result of the Life Sciences Study Group formed by the National Council of Churches of Singapore under the chairmanship of Bishop Dr Robert Solomon. The book also considers the Human Genome Project and Genetically Modified Food from a Christian perspective. It is available for $13 at good bookshops.