The past half century has seen a revolution in reproduction technology. The release of “the pill” in 1960 allowed extensive changes in the role of women in families and wider society.
We have now moved past human in vitro fertilisation (“test tube babies”) in 1978 and the “abortion pill” (RU486) in the 1980s to a point where, in recent years, we have cloned a number of mammals. There have even been rather bizarre (but unsubstantiated) claims of human cloning. The possibilities seem to be limited only by our ability to conceive them. The realities are, of course, limited by ethics committees and legislation.
Our ability to interfere with the “creation” of human life causes distress in some religious circles and both the faithful and scientists studying reproduction can find themselves tied up in complex arguments about exactly when human life begins and whether it is morally permissible to create it or terminate it.
When does a human become human? Is it at the moment of conception when a sperm cell fuses with an egg? Or is it at implantation when the fertilised egg escapes the possibility of being lost from the womb and can begin to develop and grow? Is it later when the cells of the brain are first specified or later still when the fetus’ complexity is such that it is undeniably and recognisably human?
As a researcher in developmental genetics (the study of how genes control embryo development) I would like to put in my two cents worth to remind the faithful and even some scientific colleagues of one basic fact. Human life never begins!
Human life never begins because sperm cells and egg cells are not dead. Look down a microscope at a rapidly wriggling sperm cell and you will observe that it is very much alive!
In fact, a sperm cell can be thought of as a kind of stripped-down gene missile. Its sole purpose is to deliver to the egg one copy of the set of human genes (the “genome”). A sperm connects with an egg and uses its armour-piercing warhead to breach the egg’s protective coat and deliver its genome package. It gives very little else to the embryo. Most of the cellular machinery of the newly formed embryo is contributed by the egg.
When a sperm cell and egg cell merge the most important feature of the new cell is that it has two copies of the human genome rather than one. In genetics parlance we say that the “haploid” sperm and egg cells (with one genome copy each) have fused to form a “diploid” cell with two genome copies. The new diploid cell carries a unique combination of gene variants inherited from the mother and father but, other than that, it is just a cell.
Or is it? Does a soul enter this diploid cell when it is formed? Is diploidy a holy state? Does having two copies of all genes somehow take a cell to a new spiritual level with haploidy being some lesser state of existence? I do not have any answers to these questions since I have no way of detecting or measuring the soul or any other aspect of spirituality.
Having been reminded of the basic biological fact that human life never begins we should look at some of the implications:
- the living cells that make up our bodies are the end result of a continuous living line going back almost 4 billion years;
- each human has literally billions, if not trillions, of ancestors. Only a tiny fraction of these ancestors are humans from the last 100,000 to 200,000 years since our species arose. Before that the ancestors were non-human. By comparing the information coded in the genes of animals, plants, fungi and bacteria it is crystal clear that all life on Earth is, ultimately, derived from one original cell;
- the only reason that any of you are reading this today is because EVERY ONE of your billions or trillions of ancestors succeeded in reproduction. The chances of this are almost infinitesimally small so, in a sense, each of us has won the world’s greatest lottery just by being born; and
- by the same logic, it is somewhat tragic when any one of us does not manage to reproduce during our lifetime. This means that, for that individual, a continuous line of life stretching back almost 4 billion years ends with them. Their genes - that share a direct ancestry with those in the original cell an unthinkably long time ago - will be lost. This little tragedy is repeated countless times every day.
Since human life never begins we need to reframe the ethical debate on reproductive technology. We need to define what it means to be human and when, during its development, an embryo first shows these characteristics.
Presumably, any definition of humanity will involve the development of our uniquely capable brain. However, we also need to remember that, since all living things share a common ancestry, “humanity” may not be an exclusively human characteristic. Some believe an adult orang-utan to have the mental capacity of a five-year-old human child and chimpanzees can be taught a fairly sophisticated form of human sign language.
By refocusing the ethics of human reproductive technology around the biology of embryo development we can begin to see ourselves in the eyes of our non-human relatives.
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