Preimplantation diagnosis and ethical status of the human embryo
Gonzalo Herranz, department of Bioethics, University of Navarra, Spain.
International Congress: Our Future is Life. Humanae Vitae towards the 21st Century
CRC. Institute for Biomedical & Family Ethics
Manila, September 22-24, 1995
Introduction: Progress and ethical responsibility
Genetic diagnosis of the pre-implantation embryo
A response from medical ethics
The embryo as a product of laboratory
A double conclusion: Flawed, but human from the start
Introduction: Progress and ethical responsibility
The adventure of embryofetal medicine is just beginning. It already offers us very impressive firsts, but, above all, promises that are very broad and difficult to estimate. It is worth reflecting seriously on them, especially those concerning the early embryo, because they have far-reaching ethical implications.
Manipulations on the young human embryo have become possible thanks to the confluence of two recently created medical subspecialties. Firstly, from Reproductive Medicine, Procreatic Medicine, as some say: thanks to advances in the understanding of the mechanisms that are at the physical basis of the transmission of human life, our knowledge about the biology and diseases of the young embryo has multiplied. Secondly, from the medical Genetics : much has been done and will continue to be done by the modern Genetics, especially the molecular Genetics , to understand the making of the human body: to understand how the traits that characterize us are built, how the advantages and also the weaknesses that we inherit are constituted, and, hopefully, how genetic errors can be corrected. The Genetics is no longer just an explanatory and predictive science: it is becoming curative. In the future, geneticists will not only diagnose and advise: they will be efficient therapists.
However, even now, as clinical embryology and medical Genetics experience technical progress, they are accumulating ethical problems. Like so many other medical specialties, they find themselves at a time when they have to face a fundamental decision: either to serve man or to dominate him; to respect his life or to relativize it.
Unfortunately, the opportunities offered by clinical embryology are, for the moment, mostly linked to assisted reproduction techniques. Young embryos in vitro can be subjected to diagnostic tests to determine the presence of chromosomal and genetic abnormalities. Once the diagnosis of disease has been established, there are two possible courses of action: either to kill the embryo by what Edwards called in vitro abortion; or to recognize it as a sick human being, with the right both to live with the limitations of the disease Genetics, and to receive curative or palliative treatment.
This is the marvel. In recent years, ingenious techniques have been developed to isolate genes, multiply them in vitro by means of the DNA polymerase chain reaction, and thus create gene libraries that are extremely useful for diagnosis and, as is beginning to be glimpsed and put on internship, for the eventual correction of a growing issue of diseases. Indeed, as new technical possibilities are explored for gene transfer, i.e., for including in the genome of cells the DNA fragment corresponding to a gene, an ever wider gap is opening up to the possibility of gene therapy. The therapy of gene defects is now a reality, although still in its infancy: there are still many things to learn before it can be fully accepted as part of the medical art.
Embryonic cells, blastomeres and stem cells of different tissues are revealing fascinating properties in experimental programs of study , in vitro as well as in vivo. We are gradually learning about modulatory substances that act as growth and differentiation factors and that modify, sometimes surprisingly, the spontaneous behavior of these cells. This can have wonderful consequences for the cure of many diseases, both to cure deficiencies in the embryo itself and, by means of transplants, to treat other patients. The new Embryology is, after all, a land of promise, something so important that it is worth thinking and talking very seriously about it.
In order to do so, two groups of data and considerations should be taken into account. Firstly, the current state of embryo gene diagnosis and therapy. Secondly, the ethical and social consequences of the new Embryology. plenary session of the Executive Council Because this has to decide whether the human embryo is a member of our family by right, deserving the utmost respect, or whether it is simply a cellular accumulation, lacking the dignity of man, which can be manipulated and used.
Precisely how we treat the youngest human embryos is one of the most critical touchstones of bioethics.
Genetic diagnosis of the pre-implantation embryo
In principle, genetic diagnosis of the embryo in vitro is of interest in two types of situations. In one, it is a matter of detecting genetic alterations of relatively high incidence, but which occur without a history of disease Genetics in the parents or siblings. In the other, we are dealing with diseases of known hereditary transmission, in which there is an immediate history in the same family.
In the first case, therefore, it is a more or less systematic genetic screening of the general population or sectors of the population at higher risk: a typical example is the detection of trisomy 21, the determinant of Down syndrome, which is offered in many countries to pregnant women over 35 or 40 years of age. In the latter case, the aim is to determine which members of the family are candidates for having, or transmitting, the disease Genetics.
These genetic programs of study can be done during gestation, in connection, unfortunately, often with the elimination of the defective embryo, which is authorized by law in many countries. But it is also possible to genetically analyze the embryo before its implantation in the uterine wall, taking advantage of the in vitro phase of in vitro fertilization. However, as is well known and as the Declaration Donum vitae accurately pointed out, this entails insurmountable ethical difficulties from the point of view of Catholic morality. One could also examine, in a more technically remote alternative, but much more ethically acceptable, the naturally conceived embryo recovered from the tube by the technique of tubal lavage.
Once the embryo has been obtained, it is possible to diagnose very gross genetic alterations by simple microscopic observation of the zygote. Thus, at the end of fertilization, instead of the two normal pronuclei, three pronuclei can be seen inside the ovular cytoplasm, either because two sperm penetrated it or because the second polar corpuscle was not eliminated. The status then created is of extreme biological gravity. The development of these triploid eggs (with three haploid chromosome endowments) gives rise to an abnormal development with early death of the embryo.
Attempts have been made, by microsurgery, to free the triploid embryo from the excess nucleus. The operation requires a great deal of skill and good fortune: only very few have been able to complete it successfully, as the trauma involved in the introduction of the micropipette and the aspiration of the excess nucleus is very strong. Moreover, the correct performance of the operation requires the removal of not simply one of the three pronuclei present, but specifically one of the two that is in excess. A mistake here would have dire consequences, since it would leave the fertilized ovum with two pronuclei of the same sexual origin, the two maternal or the two paternal, and the entities that develop from them are aberrant biological Structures (teratomas, in one case, or androgenic hydatidiform molas, in the other). The problem of triploidy is not very significant in ordinary human reproduction; it is in assisted reproduction, where 5% of oocytes fertilized in vitro have three or more pronuclei.
The greatest hopes are currently pinned on the application of genetic diagnostic techniques, through karyotype analysis or the use of gene probes. This makes it possible to determine which zygotes are normal and which are affected by a disease Genetics. The incidence of chromosomal alterations in the zygote is very high. This is not surprising, since chromosomal abnormalities have been found to occur in 35% of unfertilized oocytes (nullisomies and, above all, dysomies, affecting any chromosome). In embryos, the level of chromosomal abnormalities has been estimated at between 23% and 40%. These are either pre-existing alterations of the gametes or errors produced during fertilization, which seem to occur more frequently in cases of infertility, perhaps linked to advanced maternal age, to ovarian hyperstimulation or to the artificial conditions under which in vitro fertilization takes place.
To make these fine diagnoses, it is necessary to resort to preimplantation embryo biopsy techniques. It is not easy, because it is necessary to remove enough cells from the embryo to make a safe diagnosis, without compromising the subsequent development of the embryo. There are also time constraints. The embryo biopsy must be performed within a chronological window: if we take cells at a very early stage (embryo with very few blastomeres), the embryo may not develop or may do so with defects; if we act at the late blastocyst stage, the embryo may already be incapable of nesting in the uterus.
The work program for gene diagnosis of the preimplantation embryo goes something like this: the zygote is cultured in vitro until it becomes an embryo of four, eight or more cells. The pellucid membrane is then pierced with the financial aid of a cutting micropipette or by applying acid Tyrode's solution (it should not be used in the human embryo, as it is too aggressive), and one or more blastomeres are extracted by aspiration, extrusion, or mechanical cleavage. The procedure itself requires an extraordinary skill of micromanipulation. If the embryo is already at the blastocyst stage, a group of cytotrophoblast cells, which will form the placenta, can be split or herniated through the pellucida. If the diagnostic technique requires some time, it is necessary to freeze the embryo at a very high temperature leave for the time necessary to obtain the results, especially when it is necessary to culture the extracted cells, since it is easier and safer to work with many cells than with few. Karyotypes can be obtained to detect chromosomal abnormalities, or programs of study hybridization using in situ gene probes, the efficient DNA-polymerase chain reaction technique can be applied.
As these preimplantation genetic diagnosis techniques are applied today, they can be considered as an unfortunately discriminatory system. The embryo is subjected to a perfection screening: if it complies with requirements of normality/acceptability, it is transferred to the uterus. If it does not meet the quality requirements of requirements , it is discarded.
And why not cure these sick embryos? Therapeutics for diseases of the zygote or the young embryo is not yet developed. For the time being, the dominant ideas on this subject are not on the right track.
From the technical point of view, we are still in a very incipient phase. The ethical discussion on the subject is full of surprising contradictions. Only the voice of the Church has sounded univocal and full of compassion.
At academic community and in society there is now an almost universal consensus on one point: that of considering gene therapy of somatic cells, to which there are no particular ethical objections, and gene therapy of germ cells (gametes, zygotes and young embryos), which is either forbidden by law or subject to an indefinite moratorium, as two completely different areas. Behind this consensus are both the fear that attempts at gene therapy may be accompanied by transmissible damage to progeny, which is a prudent and reasonable fear, and the rejection of the possibility that gene therapy could be used as a tool for such things as race improvement, the production of supermen or the like. It is repeatedly stated that one cannot ethically address the question of gene therapy of the embryo or germ cells until extensive and satisfactory experience has been gained about the manipulation Genetics of somatic cells.
This gives us a long deadline to mature the answer to the fundamental question: Should the embryo be medically treated as one of us? Is it a human being of the same rank as us or, on the contrary, is it an inferior being that can be treated differently? What is, in fact, the ethical rank of the human embryo? What do people think of it, of its nature, of its rights?
The content and energy with which the different attitudes on the ethical status of the human embryo are manifested cover a very broad spectrum, which is a translation of the different ideas about how to become a human being, or what it means to be a human being, of the religious and cultural traditions on the respect due to nascent human life, of the acceptance or rejection of the deficiency, of the relaxation of the collective conscience towards the value of human life, which in today's society has introduced the decriminalization of abortion.
There are many contradictions between the legal norms or ethical guidelines published to date. Thus, a resolution of the European Parliament in 1988 proposes, with regard to engineering interventions Genetics on the human germ chain, that all experiments seeking to modify arbitrarily the genetic program of human beings be prohibited; that criminal sanctions be imposed on those who transfer genes into human gametes; that a definition of the legal status of the human embryo be agreed upon to guarantee the precise safeguarding of its identity; that a definition of the legal status of the human embryo be agreed upon that guarantees the precise safeguarding of its identity Genetics; and that it be established by law that any partial modification of the hereditary heritage constitutes a falsification of human identity, which is inadmissible and unjustifiable insofar as it is a highly valuable legal asset staff. The European Parliament does not distinguish between therapeutic intervention and enhancement manipulation, i.e. between curing the sick and creating gifted individuals.
At the opposite extreme, we have the guidelines of the American Academy of Pediatrics, which oppose any prohibition that might limit the development of gene therapy in man and strongly condemns limitations on the freedom of research in this field.
I would like to comment, as being more coherent with the healing ethos of Medicine, on the deontological rule in force in Spain, which could serve as model of rule respectful of life and in favor of scientific progress.
A response from medical ethics
The article 25.2 of the current Code of Ethics and Medical Deontology of the Spanish Medical Association reads as follows: The sick embryofetal human being should be treated agreement with the same ethical guidelines, including the informed consent of the progenitors, that inspire the diagnosis, prevention, therapeutics and research applied to other patients.
By regulating in this article the relationship between the physician and his embryo-fetal patient, the Code assigns to the physician the role of protector of the life that is beginning while extending to the embryo and fetus the ethical prerogatives that medicine recognizes to all human beings. The continuity of human life imposes the continuity of ethical respect and of the medical attendance , with its diagnostic, preventive and therapeutic services.
The nascent Embryofetal Medicine is a medical specialization program conditioned by peculiar characteristics of biology and pathology in the different ages of man. It has therefore the same raison d'être as Neonatology, Pediatrics or Geriatrics, and obeys the ethical rules common to all Medicine. Its interventions are guided by the same criteria of efficiency and tolerable risk. Just as in postnatal medicine a policy of eliminating worthless lives is not tolerable, in prenatal medicine genetic screening or the systematic destruction of sick or simply excessive embryos or fetuses is not tolerable at issue.
The human being, before birth, if he is sick, must benefit from medical progress. In today's medicine, the embryo, like the fetus, must be considered as just another patient. It is not a biological object of inferior rank that can be eliminated in good conscience. The human embryo is open to all scientific initiatives, on condition that it is respected. The moratorium on genetic interventions on germ cells has a character provisional, it is conditioned by the rudimentary nature of our technology. It cannot be a permanent decision, expressive of the lack of ethical values of the embryo. It would be an ethical absurdity to prevent the application of germ line gene therapy which, respectful of nascent life and the dignity of procreation, would cure the embryo, freeing it and all its descendants from the genetic error that it has inherited from its parents.
Embryofetal medicine realizes the true purpose of medicine. It is a genuinely medical and ethical specialization program . On the contrary, abortion as a treatment for acquired embryofetal disease or inherited error is not. Embryofetal medicine is born from the alliance between medical respect for the weak and biomedical research . Eugenic abortion, on the other hand, is based on the discriminatory idea that there are inferior human beings who can be discarded. This contradiction brings us face to face with the different answers that have been given to a decisive question:
One of the most significant battles of Bioethics is being fought today around this question.
It is curious that these tiny human beings, which were practically unheard of until a few years ago, have acquired a decisive symbolic value. They have gone from being in an inaccessible limbo to occupying a central place in the ethical discussion, in such a way that one can anticipate that the destiny of humanity will be strongly determined by the answer to the question of whether the human embryo is a thing, or an intermediate entity yet to be defined, or whether it is a man. The notion that ends up prevailing will set the moral tone of the society of the future. It will determine, in the end, a decisive part of inter-human relations.
The embryo as a product of laboratory
If a survey were to be made today among experts in medical embryology about what or who the embryo is, and what are the moral requirements that the embryo demands from us, most of them would answer with the well-known "Don't know, don't answer".
This ignorance is a recent phenomenon. Because until the advent of in vitro fertilization, any book on human embryology began more or less as follows: "The development of a human individual begins with fertilization, a phenomenon by virtue of which two highly specialized cells, the spermatozoon of the male and the oocyte of the female, unite and give rise to a new organism, the zygote". But today, this no longer seems to be the case. It seems as if direct visual observation of the always surprising phenomenon of fertilization produces opposite effects among scientists. For some, the observation of the mysterious simplicity with which a new man is engendered brings a lasting smile of astonishment. Others do not seem to accept such a humble genesis for man. The reason is not biological, but political. Only by depriving the preimplantation embryo of its human character can we ethically neutralize the considerable loss of embryos that in vitro fertilization entails. In vitro fertilizers are interested in affirming that the zygote is something irrelevant, a molecular product devoid of human form and value. They insist that fertilization is a relatively banal moment, without the significance and transcendence that others attribute to it. I cannot resist referring to what R. G. Edwards says in defense of this point of view: "The research on embryos raises the question of the fundamental rights of the human embryo, issues such as when life begins, or whether embryos have any rights at all. The embryos we are talking about are tiny: thousands of them could fit in the volume of a single drop. They are tiny clumps of cells; they have no hands, feet, or head. They change shape, but under none of them have the slightest resemblance to a human being until seven weeks of gestation have passed. And yet there is a crying ethical question surrounding these tiny specks of life, questions in which the opportunities to do good conflict with the value placed on incipient life.
Some people object to working with human embryos because they believe that life begins with fertilization. Those who think this way are in fundamental error, because they oppose the programs of study on in vitro fertilization and its applications. They use the absolutist argument that, with fertilization, the embryo receives all human rights. They say that the embryo is equivalent to a child or an adult, and that destroying embryos at research is the same as killing adults. I," Edwards continues, "cannot share this view. The biological facts lead to very divergent moral conclusions.
Life is a continuum: it does not begin at any given moment. As alive as the embryo are the sperm and the oocyte that gave rise to it. The originality and unrepeatability Genetics of the sperm and the oocyte is no less than that of the new embryo; after all, the latter has received them from its precursor cells, which are cells lacking special ethical requirements. There are no reference letter points between which a line can be drawn between life and non-life. There are too many arguments and exceptions to accept that fertilization is the beginning of life." Edwards then refers to how many children with Down syndrome present a mixture, a mosaic, of normal and other trisomic cells, whose mutual proportion is constantly changing; to how a fertilization can give rise to a hydatidiform mole, which is not a human being at all; to how a parthenogenetic development is possible, without fertilization, which in some animal species reaches a very advanced Degree of development . And returning to more beaten paths, he wonders how fertilization can be the beginning of life if we know that some embryos can fuse and form genetic chimeras or that an embryo can split days after fertilization to give rise to two or more identical twins; or that a high proportion of the products of fertilization are a resounding biological failure condemned to die. And he concludes: "Fertilization is merely one more stage, one stage in a long, complex and continuous process, so that choosing it as the beginning of life is as arbitrary as choosing any other. Fertilization is only one step in a person's development . The oocyte gradually develops into an embryo, and any line to mark when the embryo's rights begin is arbitrary. For my part, I would suggest that the period from 12 to 30 days after fertilization is a time worthy of study, as this is when nerve tissue begins to form." In contrast to the "conceptionist" point of view of classical Embryology - one is human from the first moment - this "developmentalist" view was very strongly consolidated, following the publication of the influential report of committee Warnock, whose prestige is based, precisely, on his agnostic character, in having refrained from defining the humanity of the embryo. He fixed in an arbitrary deadline of 14 days post-fertilization the period in which the destructive research of embryos could be authorized, something that, surprisingly, has had a spectacular acceptance in the scientific establishment and in many of the legislations enacted up to now.
The term pre-embryo, which has made so much fortune, has given a semblance of scientific respectability to that administrative deadline of 14 days in which the period of lack of human rights of the primitive embryo ends. It has been imposed not because it is in itself significant of some biological reality, but because it serves to validate qualification or ethically neutralize the loss or deliberate destruction of embryos that is inevitably linked to assisted reproduction procedures, to the research on embryos, to abortive contraception and to counter-management. The notion of the pre-embryo stripped of dignity and human rights has been a kind of plenary indulgence for the dark side of medical interventions on human reproduction.
The early human embryo, in this reductionist version, is an ethically neutral entity, so that our relations with it have no moral significance. The manipulation and destruction of young human embryos is of no concern to the law, as long as such operations are carried out with the authorization of an administrative control agency.
In contrast to the utilitarian warnockian doctrine of the embryo-thing, the Vatican Instruction Donum vitae imposes respect as an ethical attitude towards nascent human life, towards the embryo-man. According to Donum vitae, all human beings are to be loved equally and all are to be respected as human persons from the moment of conception. Wherever it happens - in places as morally disparate as within marriage or outside of it, in the aggressive injustice of rape or in the aseptic conditions of a tube at essay- conception always inaugurates a human life, which does not belong to the father or the mother, but to a human being that develops on its own and that would never become human if it were not already human at its very biological beginning. The embryo is ethically an equal to us. If it is sick, we must treat it according to the best and most beneficial advances of biomedical science, that is, diagnose it and apply the appropriate therapies, always respecting its uniqueness staff. Prenatal diagnosis and therapeutic interventions on the human embryo are licit if they respect its life and integrity, if they seek its cure and well-being.
The Instruction Donum vitae uses very simple, respectful and compassionate language and, contrary to what many have reproached it for, it is open to scientific audacity and modernity. It does not volatilize the embryo or submerge it in a stratum of subhumanity. On the contrary, it confers full rights on the embryo and makes it a participant in all the ethical requirements conferred on human beings.
This very encouraging and positive doctrine of the Vatican Instruction has been the object of much scorn or unjust silence, while report Warnock has been given a flattering and gratuitous propaganda. But I will not tire of insisting that, in the midst of the exuberant proliferation of guidelines and recommendations on human embryonic experimentation, only Donum vitae is maximally open and consistent. Apart from it, no other has shown fidelity to the Declaration of Helsinki. The Vatican Instruction endorses the idea that the interests of science or society can never prevail over those of the individual, including the embryonic individual; it points out that research cannot become a destructive manipulation of human beings; it advocates the free and voluntary consent of the subjects of experimentation.
A double conclusion: Flawed, but human from the start
With the humble appearance of a nascent embryo, each one of us begins our own existence. Our biography has this minimal and, at the same time, glorious beginning. No one becomes a man without starting there. If the first 14 days of our existence were suppressed, no one would become a man. In those days the human embryo makes the most important biological decisions. By means of urgent biochemical messages, it changes the physiology of the maternal organism, which is fully subjected to its service. We have all been unicellular embryos and, having been so, we have become capable of being what we are now. To deny embryos the right to humanity is a cruel injustice, it is to deny ourselves our human origin.
Said the classic: I am human and I do not renounce anything human. None of us can renounce that humble origin. Every human being is engendered under the appearance of a cell. The day this happens, he reaches the highest concentration of humanity per unit of volume, because it is the day God creates him in his image and likeness: a single-celled, microscopic image for the moment, but full of power and meaning.
What happens in the early days of our life, what happens in the nascent life, is to never cease to amaze us. Lewis Thomas has said it with inimitable grace. You start from a single cell that comes from the fusion of a sperm and an oocyte. The cell divides into two, then four, then eight, and so it goes on. And, very soon, at a certain moment, it turns out that among them appears one that is going to be the precursor of the human brain. The mere existence of that cell is the first of the wonders of the world. As long as it was awake, people should be commenting on that fact. They should be calling each other all day long, in inexhaustible amazement, to talk about that cell alone. But there it is, perched in its place in every one of the billions of human embryos in all history, from every part of the world, as if it were the easiest and most ordinary thing in life.
If you want to live from surprise to surprise, here is the source of them all. One cell is differentiated to produce the massive apparatus of trillions of cells, to think, to imagine, and also, for that matter, to stay in one piece in the face of such a formidable surprise. All the information necessary to learn to read and write, to play the piano, to argue before a committee of congress, to cross the street in traffic, or to perform that wonderfully human act of stretching out one's arm and leaning against a tree: all that is contained in that first cell. It contains all the grammar, all the syntax, all the arithmetic, all the music.
It is not known how this differentiation takes place. At the very beginning of the embryo, when it is nothing more than a pile of cells, it seems that all that information and much more is latent in each of its cells. When the stem cell of the brain appears, it connects what is going to determine its cerebrality, and, at the same time, all the other potentialities are disconnected, in such a way that this cell can no longer choose, as its precursors could do, to become a thyroid or liver cell, or any other thing. It can only be a brain.
Nobody has the faintest idea how that is done, but the truth is that nothing in this world is more interesting. If, before I die," Lewis Thomas concludes, "someone finds the explanation, I would do something crazy: I would rent one of those planes that can write in the sky, a whole squadron of those planes, and I would send them around the sky of the world to write one exclamation mark after another, until the money runs out.
I believe that it is with this enthusiasm for life that we must deal with the biology and ethics of the human embryo. And we need this enthusiasm for life to welcome, to face congenital deficiency, inherited error. The modern Genetics has taught us a consoling truth: that being different from one another is a priceless biological good. Diversity Genetics confers on each human being the privilege of being original, different from all others, unique and unrepeatable. This gives our successes and our mistakes an immeasurable value. With individual diversity come to the human family many blessings, some biological and others personal and social, that make us capable of adapting to the thousand circumstances outside and, above all, of always and continuously being each one of us a box of surprises for ourselves and for others.
The miracle of diversity emerges, in part, from the fact that meiosis assigns to each gamete and, consequently, to each of us, an exact dose of DNA whose nucleotide sequence is original and unrepeatable. The truly great thing about diversity is not simply that molecular diversity: it is the fact that each one of us is capable of making of the universe and all that it contains his own, unique, inimitable version, an interpretation that only he can execute in his own, staff and different register.
Truly, diversity is the salt and pepper of life. Like everything valuable, the treasure of diversity has had to be bought at a high price. Because in order for the very delicate and complex molecular and cellular mechanisms that create and maintain the biological basis of diversity to function, there is a risk that they will malfunction from time to time: they then express themselves in a motley variety of anomalies and diseases. Disease Genetics is an inevitable companion of life, because the most surprising property of our genetic material, of our DNA, consists precisely in its capacity to be a very fixed molecule and, at the same time, capable of changing, of breaking, of recombining, of committing small blunders. We could not be the way we are if we were not willing to pay for our advantages with a few mistakes, with attempts that fail, with failed trials. The alterations of the genetic heritage are the necessary accompaniment of the advantages we have acquired with it. Mistakes are as human as successes. Normal men and women are as human as men and women marked by deficiency Genetics.
Therefore, the right to have genetic defects is a fundamental human right, because error is part of our biological essence. Therefore, we all have a moral obligation to be understanding and tolerant of errors, including biological ones, because they are part of the inheritance we have received: none of us is free of them. We cannot be racists of normality.
We must defend with determination the human and universal right to live with genetic defects without being bothered or discriminated for it. And also the right to receive from the Medicine who needs it the financial aid to cure or mitigate the disease Genetics, making it tolerable for the one who suffers it and for those around him.
To achieve this, we need both a lot of science and a lot of true compassion. We need to grow in tolerance towards diversity and towards biological handicap. A tolerance that in the future will be as essential to society as religious tolerance and ideological tolerance. And whose conquest and maintenance will be just as costly. That is the great challenge that lies ahead of us: our understanding and tolerance must grow in step with our scientific progress. We cannot be tyrants of normality. That is what the pre-implanted embryo, the smallest of our siblings, demands of us.