Human Cloning and Human Dignity:
An Ethical Inquiry
The President's Council on Bioethics
We begin our presentation of the important matter of terminology by listing the crucial terms used in this report:
- Human cloning.
- Cloned human embryo.
The rest of this chapter will develop the meaning of these terms and provide the analysis and argumentation that have led us to these choices. Because there is much to be learned about the subject through the discussion of alternative terminologies, and because we believe strongly that the judicious use of language is necessary for sound moral choice, we present our discussion of this matter at some length.
Introduction: The Importance of
Careful Use of Names
Fruitful discussion of the ethical and policy issues raised by the prospects of human cloning as with any other matter can proceed only if we can find appropriate and agreed-upon terms for describing the processes and products involved. Before we can get to possible moral or policy arguments or disagreements, we need to agree about what to call that about which we are arguing. As a contribution to public understanding, we emphasize that this is not an easy thing to do, and we indicate how and why we have gone about making our terminological choices.
What exactly is meant by the term "cloning"? What criterion justifies naming an entity a "clone"? How is the term "cloning" related to what scientists call "somatic cell nuclear transfer (SCNT)" or "nuclear transplantation"? What should we call the single-cell entity that results from SCNT, and what should we call it once it starts to divide and develop? How, if at all, should our names for such activities or such entities be affected by the purposes we have for engaging in the activities or for using the entities?
As these questions imply, there is much confusion today about the terms used in discussing human cloning. There is honest disagreement about what names should be used, and there are also attempts to select and use terms in order to gain advantage for a particular moral or policy position. One difficulty is the difference between the perspective of science and the perspective of lived human experience. People who look at the phenomena of human reproduction and development through the lens of science will see and describe things in terms that often differ widely from those in ordinary usage; moreover, when an ordinary term is used in scientific parlance, it sometimes is given a different meaning. Similar divergences are possible also for people who look at these matters through the lens of different cultural, philosophical, or religious beliefs. Yet at the same time, all of us scientists or not, believers or not encounter these same matters on the plane of lived human experience, for which the terms of everyday speech may well be more suitable. Because this same common (nonscientific) discourse is also the medium of discourse for the ethical and policy discussions, we shall strive to stay close to common speech, while at the same time making the best use we can of scientific findings to avoid mistakes and misconceptions.
Advisers to decision makers should strive not only for accuracy, but also for fairness, especially because the choice of names can decisively affect the way questions are posed and, hence, how answers are given. The issue is not a matter of semantics; it is a matter of trying fairly to call things by names that correctly describe them, of trying to fit speech to fact as best one can. For the sake of clarity, we should at least stipulate clearly the meanings we intend by our use of terms. But we should also try to choose terms that most accurately convey the descriptive reality of the matter at hand. If this is well done, the moral arguments can then proceed on the merits, without distortion by linguistic sloppiness or chicanery.
Many of the terms that appear in the debate about cloning are confusing or are used in a confused manner.
First, there are difficulties concerning the terms that seek to name the activity or activities involved: cloning, asexual reproduction, reproductive cloning, nonreproductive cloning, research cloning, therapeutic cloning, somatic cell nuclear transfer (or nuclear transplantation), nuclear transfer for stem cell research, nuclear transplantation to produce stem cells, nuclear transfer for regenerative medicine. At stake are such questions as whether all acts of SCNT should be called cloning. Some worry that the term "cloning" unfairly prejudices people against the activity when it is used to describe research activities.
Second, there are difficulties concerning the terms that seek to name the entity or entities that result from human cloning (or human SCNT): cell, egg, activated cell, totipotent cell, clonote, reconstituted (or reconstructed) egg, zygote, clump of cells, embryo, human embryo, human organism, blastocyst, clonocyst, potential human being, human being, human clone, person. At stake here is the nature and the possible moral status of the entities that are involved in the subsequent manipulations, whether for producing a child or for use in biomedical research. Some worry that use of any term but "embryo" will unfairly prejudice people in favor of embryo-destructive activities by hiding from view the full import of the activity.
Third, there are difficulties concerning the terms that seek to describe the relation between the cloned entity and the person whose somatic cell nucleus was transferred to produce the cloned entity: genetic copy, replica, genetically virtually identical, noncontemporary twin, delayed genetic twin, clone.
Tools of Analysis
As a prelude to examining the activity or the deed of cloning, some general analytical observations will be helpful. Although all aspects of an activity or action are relevant to understanding its full human meaning, when describing a deed it is sometimes useful to distinguish what it is from both how it is done and why it is done. The act itself (what) may be accomplished by a variety of means or techniques (how), and it may be undertaken for a variety of motives or purposes (why). To be sure, there is a danger of distortion in this disaggregating analysis of human activity, and there is disagreement about the degree to which the motives or purposes of the agent are to be reckoned in the description of the act itself. People argue, for example, whether "mercy killing" differs as an act from murdering a rival (or executing a murderer or killing someone in self-defense), or whether they are all equally acts of homicide (literally, "killing a human being") whose moral meaning ("Is it justified or not?" "Is it wrong or not?") we can then proceed to debate, if we wish, by attending not only to the bare act of taking a human life but also to the agent's motive and purpose. Though we do not wish to beg this question, the very existence of this disagreement suggests that we do well not to ignore the naked act itself, for it may have a meaning independent of what moved the agent, a meaning relevant to subsequent moral assessment that we do not wish to overlook.
To illustrate: in vitro fertilization (IVF: the merging of egg and sperm outside the human body [in vitro = "in glass"], yielding a zygote that is the beginning stage of a new living being) is the deed (what). It is an act of "fertilization," of making fertile, of making the egg cell ready and able to develop into a human organism. This fertilization may be accomplished in at least two ways (how): by merely mixing egg and sperm, allowing the sperm to find and penetrate the egg, or by the technique of injecting individual sperm directly into the egg (a technique known as intracytoplasmic sperm injection, ICSI). And it may be done for the (proximate) purpose (why) of initiating a pregnancy, in turn for the (ultimate) purpose of providing a child for an infertile couple; or it may be done for the (proximate) purpose of providing living human embryos for basic research on normal and abnormal embryological development, in turn for the (ultimate) purposes of understanding human development or of discovering cures for diseases and producing tissues for regenerative medicine. Though the technique used or the purposes served may differ, in one crucial respect the deed (IVF) remains the same and bears a common intrinsic meaning: a human zygote, the first stage of a new human being, is intentionally produced outside the body and exists in human hands and subject to human manipulation.
As it happens, this fact is more or less accurately reflected in the descriptive terminology used for IVF. Interestingly enough, unlike the situation with cloning, no one distinguishes between "reproductive IVF" and "therapeutic IVF" or "research IVF," naming the activity or deed after the motive or purpose of the agent. This may reflect the historical fact that IVF was initiated by people who were interested in using it to produce live-born children for infertile couples; the research use of "surplus" embryos produced by IVF came only later. But it happens that this common name is also descriptively apt and remains so regardless of why IVF was done in a particular case: the deed is fertilization of egg by sperm, producing a living human zygote, the first stage of the development of a new human being.
In the sense relevant here, "cloning" is a form of asexual reproduction
is another), the production of a new individual not by the chance union
of egg and sperm but by some form of replication of the genetic makeup
of a single existing or previously existing individual. (In biological
or functional terms, the core of sexual reproduction is not bodily intercourse
but the fusion of male and female germ cells; thus IVF, though
it takes place outside the body, is biologically speaking
a form of sexual reproduction.) Cloning is the activity of producing a
clone, an individual or group of individuals genetically virtually identical
to the precursor that is being "replicated."iii
In much of the current public discussion, we encounter a distinction between two sorts of cloning: "reproductive" and "therapeutic." The distinction is based entirely on the differing goals of the cloners: in the first case, the goal is the production of a (cloned) child; in the second case, the development of treatments for diseases (suffered not by the clone, but by others). We recognize the distinction and the need for terms to describe the difference. But the terms currently in vogue have their difficulties. Both terms have been criticized by partisans of several sides of the debate, and for understandable reasons.
Some object to the term "reproductive cloning" used as a term of distinction, because they argue that all cloning is reproductive. Their reason: all human cloning intends and issues in the production of a cloned human embryo, a being distinct from the components used to generate it, a new human being in the earliest stage of development or "reproduction." (This claim, we would suggest, is at this stage a descriptive point, not yet a normative one; it does not necessarily imply that such a being is fully human or "one of us," hence deserving of the moral and social protection accorded "persons.") The fact that only some of these embryonic cloned humans are wanted for baby-producing purposes does not, in the view of these critics, alter this fact about their being. In support of their claim that cloning occurs (only) at the beginning, they note that once the cloning act of nuclear transfer has occurred, all new influences that act upon the new human organism cease to be "genetic" (nature) and are now "environmental" (nurture). Instead of "reproductive cloning," we shall speak of "cloning-to-produce-children."
Although as a scientific matter "somatic cell nuclear transfer" or "nuclear
transplantation" may accurately describe the technique that is
used to produce the embryonic clone, these terms fail to convey the nature
of the deed itself, and they hide its human significance. The deed, fully
described, is the production of a living human entity (or "embryo" or
"organism"; of the right name for the product, more later) that is genetically
virtually identical to the donor organism, a fact or meaning not captured
in the name for the technique or method, the transfer of a somatic cell
nucleus (into an unfertilized egg whose own nucleus has been removed or
As a name, SCNT is not a fully accurate description even of the technique
itself. It makes no reference to the intended and direct result of the
deed of nuclear transfer. It also omits mention of the fact that the recipient
of the transferred nucleus is an (enucleated) egg cell (rather
than another kind of cell), which then can be made to initiate cell division
as if it were just like a zygote produced by fertilization. The further
amendments, "somatic cell nuclear transfer for stem cell research"
or "nuclear transplantation for regenerative medicine" or "nuclear
transplantation to produce stem cells" only compound the difficulty,
mixing in the purpose of the activity with its technique, thus further
obscuring the immediate meaning of the act itself, the production of a
living cloned human embryo.
Cloned Human Embryo: The Product of SCNT
What shall we call the product of SCNT? The technical description of the cloning method (that is, SCNT) omits all reference not only to cloning but also to the immediate product of the activity. This obscurity enables some to argue that the immediate product of SCNT is not an "embryo" but rather "an egg" or "an unfertilized egg" or "an activated cell," and that the subsequent stages of development should not be called embryos but "clumps of cells" or "activated cells." To be sure, there are genuine difficulties and perplexities regarding what names to use, for we are dealing with an entity new in our experience. Partly for this reason, some people recommend avoiding the effort to describe the nature of the product, preferring instead to allow the uses we human beings have for it to define its being, and hence its worth. But, for reasons of both truth and ethical conduct, we reject this approach as improper. We are all too familiar with instances in which some human beings have defined downward the status of other beings precisely to exploit them with impunity and with a clear conscience. Thus, despite the acknowledged difficulties in coming to know it accurately, we insist on making the effort to describe the product of SCNT as accurately and as fairly as we can.
The initial product of SCNT is, to be sure, not just a cell but an active
cell. (More precisely, it is a cell that can be activated by electric
stimulation.) But "activated cell" is much too vague to describe the activity
of which it is capable. For, once stimulated, the activity of this "cell"
produced by SCNT is nothing other than human embryological development,
initiated and directed by the cell itself. The processes of cellular growth,
chromosomal replication, cell division, and (ultimately) differentiation
into the tissues and organs of the organism are coordinated processes
under the governance of the immanent developmental plan encoded in the
cell's genetic material. In other words, the product of SCNT is an organism
in its germinal stage, and its activities are those of an integrated and
Another suggested name, better than "activated cell," is "totipotent cell" a cell that is "capable of all." But this too is ambiguous. If what is meant is that it can (and will, should it be stimulated to do so) become "any and all" of the different kinds of cells in the body, then it is an insufficient meaning. For, as explained in the previous paragraph, this totipotent cell may also become the "all" that is the integrated whole (cloned) mature organism itself (along with a portion of the placenta that would give it nourishment). In this second and fuller meaning of "totipotent," a totipotent cell is then just a functional synonym for the "zygote": "zygote" etymologically reminds one of the cell's origins in egg-joined-to-sperm; "totipotency" describes what it is capable of. A fertilized egg is precisely a "totipotent" cell; the product of human SCNT is, we assume, its equivalent.
In some discussions, the next few stages of the developing cloned human entity have been described as "clumps of cells." Yet, for reasons already given, this is only partially accurate. Viewed externally, under the microscope, the developing embryo will appear as two, then four, then eight cells "clumped" together, and the 100-to-200-cell blastocyst stage will indeed appear as a "ball of cells." Yet there is more here than meets the eye, for the "clump" is governed by an internal principle of development that shapes and directs its transformations. Thus, this ball or clump is not a mere heap or aggregate; it is a primordial and unfolding whole that functions as a whole and that is in the process of developing (or attempting to develop) into a mature whole being. Of course, if development is not pursued or not allowed to happen because of disruption, then the "clump of cells" description may be rendered accurate not just microscopically but also biologically. But as long as development continues and the developing entity is intact, that is not the case.
It would seem, then, that whatever the reason for producing it the initial product of somatic cell nuclear transfer is a living (one-celled) cloned human embryo. The immediate intention of transferring the nucleus is precisely to produce just such an entity: one that is alive (rather than nonliving), one that is human (rather than nonhuman or animal), and one that is an embryo, an entity capable of developing into an articulated organismic whole (rather than just a somatic cell capable only of replication into more of the same cell type). This is the intended primary product of performing SCNT, whether the ultimate motive or purpose is producing a live-born child from the cloned embryo or conducting scientific research on the cloned embryo. Also, the blastocyst stage that develops from this one-celled cloned embryo will be the same being, whether it is then transferred to a woman's uterus to begin a pregnancy or is used as a source of stem cells for research and possible therapy for others.
Yet, not surprisingly, objections have been raised to calling this cloned entity an "embryo," objections having to do both with its origins and with the uncertainty about the extent of its developmental potential. There are also objections having to do not with the facts but with public connotations and perceptions: for some members of the public, the word "embryos" apparently conjures images of miniature babies. If "nuclear transplantation to produce stem cells" seems to some people to be unfairly morally neutered terminology, "embryo" seems to other people to be unfairly morally loaded terminology, especially when used to describe an entity barely visible to the naked eye. We acknowledge this problem and recognize that, despite our best efforts, such difficulties in public perception probably cannot be simply corrected. But we do not regard this as sufficient reason to scrap the use of a term if it is in fact most appropriate. The other objections to calling the product of SCNT an "embryo" are not about rhetoric and politics, but about the thing itself. They should be addressed.
First, "human embryo," in the traditional scientific definition of this term, refers to the earliest stages of human development, from the zygote through roughly eight weeks of gestation, after which time it is called a fetus. Because the product of SCNT is technically not a zygote, not having come from egg and sperm, it is argued that it cannot therefore be an embryo. Second, it is said that it cannot be an embryo because it is an "artifact," something produced entirely by human artifice, "made" rather than "begotten." Third, we do not yet know for sure whether this entity can in fact develop into a baby; hence, we do not know whether it has the full developmental potential of a human embryo formed by fertilization.
There are also very important ethical reasons that support our choice. We want to be very careful not to make matters easy for ourselves. We do not want to define away the moral questions of cloning-for-biomedical-research by denying to the morally crucial element a name that makes clear that there is a moral question to be faced. Yes, there is some ground for uncertainty about the being of the product of SCNT. Yet because something is ambiguous to us does not mean that it is ambiguous in itself. Where the moral stakes are high, we should not allow our uncertainty to lead us to regard the subject in question as being anything less than it might truly be.
The product of "SCNT" is not only an embryo; it is also a clone, genetically
virtually identical to the individual that was the source of the transferred
nucleus, hence an embryonic clone of the donor. There is, to be sure,
much discussion about how close the genetic relation is between donor
and embryonic clone, and about the phenotypic similarity of the clone
to the donor. xii
Yet the goal in this process is in fact a blastocyst-stage cloned embryo
(in the case of cloning-for-biomedical-research) or a child who is genetically
virtually identical to the donor (in the case of cloning-to-produce-children);
otherwise there would be no reason to produce a cloned embryo by SCNT
rather than an (uncloned) embryo by ordinary IVF. A full and fitting name
of the developing entity produced by human SCNT is "cloned human embryo,"
a term that also allows us to remember that, thanks to its peculiar origins,
this embryo is not in all respects identical to an embryo produced by
fertilization of egg by sperm.
As if things were not difficult enough, a further complication may soon arise, following reports of successful SCNT experiments in which human somatic cells were fused with animal oocytes, and the resulting product grown to the blastocyst stage of development. What are we to call the product of this kind of cloning? And what kind of species identity does it have? According to the advance reports (based on a presentation at a scientific meeting), the stem cells extracted from the blastocyst stage were demonstrated to be human stem cells (somewhat surprisingly, the mitochondria were also human in genotype). Is this, therefore, a cloned human embryo? The only test that could settle the question implantation into a woman's uterus for attempted gestation to see if a human child results cannot ethically even be contemplated without already assuming a positive answer. In the face of uncertainty, therefore, and lest we err by overconfidence, there is prima facie reason to include even these cross-species entities in the category of "cloned human embryos." (When we come to the ethical issues of cloning-for-biomedical-research, we can consider whether this terminological judgment is matched by an ethical one.)
None of the terms available to us is entirely trouble-free. Yet the foregoing analysis leads us to the following conclusion regarding the terms best descriptive of the facts of the matter:
Human cloning (what it is): The asexual production of a new human organism that is, at all stages of development, genetically virtually identical to a currently existing or previously existing human being.
Human cloning (how it is done): It would be accomplished by introducing the nuclear material of a human somatic cell (donor) into an oocyte (egg) whose own nucleus has been removed or inactivated, yielding a product that has a human genetic constitution virtually identical to the donor of the somatic cell. This procedure is known as "somatic cell nuclear transfer" (SCNT).
Human cloning (why it is done): This same activity may be undertaken for purposes of producing children or for purposes of scientific and medical investigation and use, a distinction represented in the popular discussion by the terms "reproductive cloning" and "therapeutic cloning." We have chosen instead to use the following designations:
Cloning-to-produce-children: Production of a cloned human embryo, formed for the (proximate) purpose of initiating a pregnancy, with the (ultimate) goal of producing a child who will be genetically virtually identical to a currently existing or previously existing individual.
Cloning-for-biomedical-research: Production of a cloned human embryo, formed for the (proximate) purpose of using it in research or for extracting its stem cells, with the (ultimate) goals of gaining scientific knowledge of normal and abnormal development and of developing cures for human diseases.
Cloned human embryo: (a) The immediate and developing product of the initial act of cloning, accomplished by SCNT. (b) A human embryo resulting from the somatic cell nuclear transfer process (as contrasted with a human embryo arising from the union of egg and sperm).
- Vogelstein, B., et al., "Please don't call it cloning!" Science, 295: 1237,
- Leggett, K. and A. Regalado, "China Stem Cell Research Surges as Western Nations
Ponder Ethics" Wall Street Journal, March 6, 2002, p. A1. Back
- A more careful analysis of the what of this activity would distinguish
between the activity itself and the product that results from it. Unlike
nonproductive activities, such as dancing ("How can we know the dancer
from the dance?"), the work (activity) of making or producing results
in separable objects or works (products). Although shoemaking completes
itself in the production of a shoe, the shoe as result is distinct
from the activity of shoemaking. Similarly, though fertilization
is an activity that is intelligible only as issuing in a fertilized
egg, the now-fertile egg as result or product stands
apart from the deed of IVF. One reason that the word "fertilization"
works so well in describing IVF is that it is a very rich term, pointing
both to cause and effect, backward to the deed and forward to the future
prospects of the product. Back
- Parthenogenesis (see Glossary of Terms), the development of an organism directly
from an unfertilized egg that has been artificially induced to undergo
development, is, in principle, another method of asexual reproduction.
Although parthenogenetic reproduction has been successfully achieved
in amphibians, in mammalian species there are as yet no reports of live
births following parthenogenesis. Thus, there is at present little reason
to believe that live-born human beings can be produced via parthenogenesis.
It is therefore not the subject of this report, although many of the
things said about cloning via somatic cell nuclear transfer would be
applicable to asexual reproduction through parthenogenesis. Back
- Although cloning, like fertilization, is responsible for bringing forth a
new organism, the activities are named in very different ways, yet in
each case emphasizing the fundamental intention of the activity. "Fertilization"
describes the activity in terms of the capacitation of the egg, as a
result of which development begins. "Cloning" describes the activity
in terms of the relation between the progenitor and the product.
In cloning by somatic cell nuclear transfer,the egg, though it is activated
as if it were fertilized, is not cloned; cloned rather is the donor
from whom the nucleus was taken, and the resulting organism (at all
stages of development) is a clone of the donor. The name of the activity,
"cloning," even more than "in vitro fertilization," refers to the product
of the activity, an identical (or nearly identical) entity. Back
- Compare, in this respect, what used to be called "therapeutic abortion," an
abortion undertaken in cases in which pregnancy threatened the life
of the pregnant woman and where abortion was therefore intended to save
the woman's life. Similarly, we might call the removal of a cancerous
kidney a "therapeutic nephrectomy"; we would never use the term to refer
to the removal of a kidney for donation to another person in transplantation.
- Pluripotent cells are those that can give rise to many different types of
differentiated cells. See Glossary of Terms. Back
- This reduction of an act to its mechanism is roughly analogous to describing
walking as "sequential alternate leg advancement" (SALA). Back
- The original egg had a haploid nucleus, containing only half the chromosomes
necessary for development. The diploid nucleus contains the full amount.
See Chapter Four.
- Technically, the term "zygote" (from a Greek root meaning "yoke") refers to
the primordial cell that forms from the union of egg and sperm and the
fusion (the yoking together) of their nuclei as the first step in the
development of a new life that has come from the joining of its two
parents. It is for this reason technically inappropriate to call the
product of an asexual initiation a "zygote," though it may be its functional
equivalent. The term "clonote" has been suggested as the strict analogue
of "zygote," identifying the primordial cell formed in cloning by its
special origin: just as a zygote arises from the "yoking together" of
two elements, so a "clonote" arises from the act of clonal
propagation from a single, already existing organism.
(Similarly, the term "parthenote" for the primary product of parthenogenesis
would accurately indicate that it arises from the "virgin" [unfertilized]
egg alone; parthenos, Greek for "virgin.") The term "clonote"
also has the merit of carrying the clonal character of the entity in
its name. Back
- For the reasons given in this paragraph, we reject the suggestion that the
immediate product of SCNT and the cells it gives rise to should be considered
"cells in tissue culture." Unlike somatic cells grown in laboratory
culture, the immediate product of SCNT, although (like cultured tissues)
it grows in culture media outside the body, is the germ of a new organism,
not merely of other cells just like itself. Back
- A recent press report indicates that as-yet-unpublished work in China
by Sheng Huizhen involved insertion of human somatic cell nuclei into
enucleated rabbit eggs, and that the resulting cloned embryos developed
to a stage where human embryonic stem cells could be isolated.2
And, of course, in other mammals the product of SCNT has been grown
all the way to live-born young that grow up to be able to produce young
of their own. Back
- Thus, for example, the report on Scientific and Medical Aspects of Human
Reproductive Cloning, released by the National Academy of Sciences
in January 2002, describes "nuclear transplantation to produce stem
cells" as "a very different procedure" from what it calls "human reproductive
cloning." Nevertheless, the report falls quite naturally into our normal
way of speaking, a way that recognizes that the cloned product is, indeed,
a human embryo and that any stem cells obtained from it would be embryonic
stem cells. Thus, for example, the authors of the report can write a
sentence such as the following (p. 2-6): "The experimental procedures
required to produce stem cells through nuclear transplantation would
consist of the transfer of a somatic cell nucleus from a patient into
an enucleated egg, the in vitro culture of the embryo to the blastocyst
stage, and the derivation of a pluripotent ES cell line from the inner
cell mass of this blastocyst." Other scientists clearly insist that
the primary product of SCNT is an embryo (see, for example, Dr. John
Gearhart's presentation to the Council on embryonic stem cells, April
25, 2002; transcript on the Council's website, www.bioethics.gov). Back
- The environment in which the donor came to be and lives surely differs from
the one in which the cloned embryo may develop (if it does develop).
There may be imprinting or epigenetic reprogramming differences in gene
expression early on that may affect the physical and mental characteristics
of the clone. There is also the matter of the mitochondrial genes (see
Glossary of Terms), a small number of protein-producing genes out of
a total of some 30,000 to 60,000, which are inherited from the female
source of the egg (the clone would be genetically identical only in
those cases in which the same woman donated both egg and somatic cell
nucleus, to produce an embryonic clone of herself). Back