Fr Angelo Serra SJ is Professor Emeritus of Human Genetics at the Sacred Heart University in Rome and is one of Europe's most prestigious geneticists. He sets out in clear terms the development of the human embryo from fertilisation.
In so doing, he provides a timely rebuttal - on the scientific level - of the claims of those who, like the Anglican Primate Archbishop Carnley, would deny the human status of the embryo until fourteen days after fertilisation and therefore support embryo stem-cell experimentation.
Fr Serra, as a specialist in the area, uses many technical terms that would be unfamiliar to most readers, but these are necessary for the proper scientific presentation of his case.
In 1986, following a false claim by an irresponsible form of science, the title and value of "child" was taken from the "newly conceived". A new life, which had just blossomed from the fusion of the maternal and paternal gametes and entered immediately into a wonderful dialogue with the parents - above all with the mother - at a biological, psychological, mental and spiritual level, the newly conceived saw itself denied the name of "child" until the 14th day after conception.
Before this day it was to be considered a "cluster of cells" and not a "human being", the gift and living expression of the love of a father and a mother. Even the law adapted itself, by denying it the "right" to exist until that day and degrading him to a mere "disposable object" up to the point of allowing it to be patented, something that we could never had imagined.
This inhuman situation was recalled in the encyclical Evangelium Vitae of John Paul II: "Some try to justify abortion by claiming that the product of conception, at least until a certain number of days, cannot yet be considered a personal human life." But he continued firmly: "In reality from the moment in which the ovum is fertilised, a new life begins which is not that of the father or of the mother but of a new human being which develops of its own accord. It would never be made human if it were not human already." And he affirms: "This has always been clear, and modern genetic science offers clear confirmation".
I will now try to illustrate, in a schematic way, this last claim made in Evangelium Vitae. In reality, rigorous scientific analysis of the early stage of the development, which follows conception and lasts about 14 days, can lead to only one conclusion: that with the fusion of the paternal and maternal gametes begins the life cycle of a "new human subject" to whom the beautiful name of "child" belongs in full and who has dignity equal to that of the father and the mother. Let us emphasise the four essential points of this analysis:
1. The first point concerns the "zygote"
At the end of the process of fertilisation, a few seconds after the fusion of one spermatozoon with an oocyte, one observes the rapid diffusion of a wave called the "calcium wave" through the whole fertilised egg, due to a temporary increase in the intracellular concentration of calcium ions and the action of oscillin - a recently discovered paternal protein. This is the signal of the activation and the beginning of the development of the embryo.
This new cell is the zygote, the single-cell embryo; a new cell which begins to operate as a new system, i.e., as a unit, an ontologically single living being, like any other cell in the process of mitosis [division] but with some peculiar properties. Among the many coordinated activities of this new cell, during a period of 20-25 hours, the most important are: 1) The organisation of the new genome, which represents the principal information and co-ordination centre for the development of the new human being and all its later activities; 2) the beginning of the first process of mitosis which leads to the two-cell embryo.
Two principal aspects of this new cell need to be stressed: the first, that the zygote has a precise identity, i.e., it is not an anonymous being; the second, that it is intrinsically oriented to a well-defined development, i.e., to form a human subject with a precise bodily form; and both these factors, identity and orientation, are essentially dependent on the genome which carries the so-called genetic information, inscribed, in well-determined molecular sequences.
In reality, this substantially invariant information establishes its belonging to the human species, defines its individual biological identity and carries a coded program which provides it with enormous morphogenetic potential, i.e., intrinsic capacities which will come into play automatically and gradually during the rigorously oriented series of new formations. A quick look at the stages of development which follow will allow us to establish, with full reason, that in fact the zygote is the exact point in space and time in which a "human individual" begins its own life cycle.
2. The first stage goes from zygote to the blastocyst (this is the second essential point of our analysis).
During a period of about five days, rapid cellular multiplication takes place under the control of a large number of genes involved in many events of cell divisions and in the production of the proteins necessary for the structure and functions of the growing number of cells. One observation merits particular note. Today it is well known that the new genome, which is constituted in the zygote, takes control of the whole series of formations from the earliest stages of development. Today all this is also evident in the science of human embryo development. After the research by P. Braude, V. Bolton and S. Moore, who proved that at least from the 4-to-8 cell stage the new genome becomes active in controlling the production of new proteins, it has been shown more recently that other genes - so far at least eight - are already active from the zygote stage.
These data, which are continually increasing with technological progress and the analysis of the genome, make it perfectly clear that the new genome, which is established at fertilisation, is the base and constant support for the structural and functional unity of the embryo, which develops along a trajectory in a constant direction. The noted embryologist, L. Wolpert, correctly noted that "the true key for understanding development lies in cellular biology, in the process of transmission of signals and the control of the expression of genes which leads to modifications in the state of the cell, movement and growth".
All this is really what happens from the zygote stage up to the blastocyst stage. In fact from the two to eight cell stage, the cells remain bound to each other by means of microvilli and cytoplasmic intercellular bridges, which facilitate the transmission of signals between the cells, which is extremely important for orderly development.
This contact becomes closer at the 8 to 32 cell morula stage, when the cells adhere more tightly together maximising their areas of contact and forming special junctional complexes which facilitate rapid intercellular passage of ions and signal molecules. This favours the process of normal development, which could otherwise be altered through the absence of even one of the junctional proteins of the connexin family.
Under the action of these signal molecules, which bring other genes into action, two types of cells differentiate in a neat way, between the third and fourth cellular cycle, and give rise respectively to the two cell lines known as trophoblast and embryoblast. This morphological and functional difference becomes more evident at the sixth and seventh cycle, when the blastocyst appears made up of 64 to 128 cells: here we can distinguish three cell types which are histologically different and have diverse destinies: the polar and mural trophoblast, derived from the differentiation of the trophoblastic cell line; the primitive ectoderm and the endoderm, which are derived from the differentiation of the embryoblast or internal cell mass (ICM).
3. Now follows the second stage, from blastocyst to embryonic disc: this is the third essential point of our analysis.
One observes the expansion of the blastocyst which frees itself of the zona pellucida by which it has been protected until now; its implantation in the uterus - which is still today called "a paradox of cellular biology" as it can not yet be easily explained with present knowledge - during which the mother and the embryo do all they can to establish a wonderful harmony despite the difficult situation; and the uninterrupted continuation of differentiation, organisation and growth.
At about the eighth day from fertilisation the amniotic cavity appears, which delimits the space where, following further differentiation, the embryonic disc is formed, a bilaminar structure derived from the differentiation of the primitive ectoderm and endoderm. Around the 10th day the amnion differentiates and the polar trophoblast with the extra-embryonic mesoderm gives origin to the chorion which becomes the fetal part of the placenta. Between the 11th and 13th days from fertilisation the embryonic disc reaches a diameter of about 0.2 mm and on approximately the 14th day a densely compact group of cells called the primitive streak appears in the caudal region, which indicates the formation of a third layer of cells, the mesoderm, and signifies the beginning of morphogenesis.
In this base structure which has been wonderfully organised in 15 days, where all development would cease if the embryonic disc were detached from the annexes with which it forms a unique whole, the general plan of the body is defined and the modelling of the different organs and tissues takes place, which is followed by organogenesis and histogenesis. In the fifth week of gestation, the primitive brain, the heart, the lungs, the gastric and genito-urinary tracts are already sketched out in the embryo, which is about 1 cm long; in the 6th week the buds of the limbs are clearly visible and at the end of the 7th week the bodily form is complete.
At this point a question arises spontaneously. If the essential outline of the development of the human zygote in the first 15 days up to the stage of embryonic disc of about 4-8 million cells, as we have traced it so far, is an objective description of what really happens, - and no one who is sufficiently informed can deny it - could one honestly affirm that at any stage of embryonic development from the zygote to the embryonic disc, human embryos are "collections of a few cells", "a mass of genetically human cells", "a bunch of more or less homogeneous cells" or "a mass of weakly organised, pre-programmed cells"; or again - as some newspapers recently quoted a Nobel Laureate as saying - that "the embryo at this state is only a cluster of cells"?
To understand more easily the gravity of these claims, which falsify the objective reality of what the human embryo is in the first 15 days of life, an analogy may be useful: no-one could describe a house built with bricks according to a well-defined structural and functional plan as a "cluster" of bricks, except in a disparaging way. Instead, the term "cluster" would be used correctly to refer to the total number of bricks with which the house is built, but when they are heaped together without any order. The former image, and not the latter, is the true image of the embryo.
At this point we must return to the question: when does the life cycle of a human individual begin? When can Dad and Mum really call the newly conceived their child (and the mother generally is already aware when he/she is completing the first five days journey along the tube)? The answer should be evident on the basis of what has been outlined so far. In any case, further consideration that is not only more descriptive but involves a logical examination of the biological process itself - defined by the great embryologist C.H. Waddington as "the continuous emergence of a form of preceding stages" or "epigenesis" - leads to a definitive conclusion. In fact, this examination highlights three characteristic properties.
The first property is co-ordination. From what has been written it is clear that embryonic development, from the fusion of the gametes up to the formation of the embryonic disc, about 14 days from fertilisation, is a process which manifests a co-ordinated sequence and interaction of molecular and cellular activities, under the control of the new genome which is, in its turn, modulated by an uninterrupted cascade of signals transmitted from cell to cell, and from the internal and external environment to the individual cells and, within them, from cytoplasm to nucleus. Precisely this undeniable property, which becomes more and more complex and rigid during morphogenesis, implies and indeed demands a rigorous unity of the being which is developing.
The more research advances, the more this unity appears to be guaranteed by the new genome, where a large number of regulatory genes ensure the exact timing, the precise placement and the specificity of the morphogenetic events. All this leads to the conclusion that the human embryo - like every other embryo - even in the earliest stages is not a "cluster of cells". Rather, the entire embryo at every stage, even in the first 14 days, is a real individual where the single cells are closely integrated in a single dynamic process through which, moment by moment, it autonomously translates its own genetic space into its own organic space.
The second property is continuity. On the basis of the facts presented it is undeniable that fertilisation begins a new cycle of life. The zygote is the "origin" of the new organism which is at the very beginning of its own cycle of life. If one considers the dynamic profile of this cycle in time, it is clear that it proceeds without interruption. This was openly recognised by the Warnock Committee in the following statements: "Once the process has begun, there is no part of the development process which is more important than any other; they are all parts of a continuous process and if every stage does not take place normally, at the right time and in the correct sequence, further development ceases".
In fact, on the basis of logical induction from the data, there is actually no first cycle of 14 days of a genetically human but anonymous living being, which ends at the embryonic disc stage, followed by a second cycle of a real human being from the embryonic disc onwards. On the contrary, there is an uninterrupted and progressive differentiation of a given human individual which begins from the stage of zygote and progresses according to a unique and rigorously defined plan. The property of continuity, therefore, implies and establishes the uniqueness and singularity of the new human subject: from conception onwards it is always the one and the same human individual with its own identity, who autonomously builds itself as it passes through stages which are ever more qualitatively complex.
The third property, the most important though generally neglected, is graduality.
The final form is reached gradually. This is an ontogenetic law, a constant of the process of gamete reproduction, according to which even a human individual must begin its life cycle as a single cell. It implies and calls for a process of regulation which must be intrinsic to each given embryo and, from the zygote stage, keeps development permanently orientated to the final form. Precisely because of this intrinsic epigenetic law, which is written into the genome, and begins to operate from the fusion of the gametes, every embryo - including the human embryo - permanently keeps his own identity, individuality and uniqueness, and remains, without interruption, the same identical individual during the whole process of development, from fertilisation onwards, despite the increasing complexity of its totality.
It is precisely these characteristics which distinguish the individual.
Therefore, logical induction from the facts offered by experimental research - which is continually growing in number and quality and rigorously confirms the present conclusion - leads to the only possible statement that at the fusion of the two gametes, except for possible disturbances, a real human individual begins its own existence, or life cycle, during which, given all necessary and sufficient conditions, it will autonomously realise all the potential with which he/she is intrinsically endowed. Therefore, the living embryo, from the fusion of the gametes, is a real individual human and not a "cluster of cells".
From that moment he is a "son": a flower that has just blossomed and deserves all love, all attention. He has the same dignity as those who gave him life, the same fundamental rights.
It is this "human" individual, always a "son", which has the right to his life. The concept of the "person" - which is not the realm of science - removes nothing from the concept of human individual; it only completes it by giving the reasons for his particular dignity, which no one can fail to recognise by reflecting on oneself.
This conclusion has obvious consequences for science, technology, medicine, society, law and politics, given that biotechnology, is more and more taking possession of society's conventional thinking and corrupting it, while refusing to yield before the overwhelming weight of scientific evidence. Prejudiced and self-interested, it continues to deceive and delude.
If what is being done today to millions of embryos had been done previously to the so-called "clusters of cells" that marked the beginning of the lives of the many scientists we admire today, with their consequent loss of life, there would indeed have been incalculable repercussions for our society.
The present article is the text of an address given in Italian by Fr Serra at the International Theological and Pastoral Congress organised by the Pontifical Council for the Family in Rome for the Jubilee Year. The translation is by John Barich of the Australian Family Association and John Kinder of the Languages Department at the University of Western Australia. This is the first time Fr Serra's important address has been made generally available in English.