Stephen E. Levick, MD

The world began to face the prospect of human cloning when the journal 

 published Dolly the sheep's "birth announcement" in the form of a letter authored by Wilmut and colleagues.

 But despite all the attention given the issue, including two presidential commissions,

 the psychological consequences of cloning have been little addressed. There being no actual human clones akin to Dolly, any such exploration would have to rely on reasoning by analogy, a necessarily risky method-but the only one available. This Viewpoint shows how one can approach cloning by analogues to it-that is, by reference to situations and phenomena that are "clone-like" in various ways.

I will address only reproductive cloning-cloning to make babies-and not cloning pursued to derive embryonic stem cells to aid in the study and treatment of disease. The current scientific consensus is that attempting to clone a human being would be unethical. Many mammalian clones do not survive to term, and those that do are often plagued with various anomalies.

But what if we eventually understand and could prevent such problems? Would there be any other cause for concern? In particular, would a clone run any psychological risks over and above those involved with simply being human?

Cloning can occur naturally when, at its first cell division, a fertilized egg, or zygote, cleaves into 2 single-celled embryos. Monozygotic twins are the result. Intentional embryo splitting in vitro,

 in which one of the early embryos is implanted and the other frozen for later implantation, would result in the birth years apart of individuals with identical DNA. Many of the issues discussed here regarding the sort of clones that are the focus of this article would also apply to such "delayed twins." Unsubstantiated claims aside, contemporaneous monozygotic twins are the only human clones that we know currently exist.

When people talk about cloning, they almost always mean cloning by somatic cell nuclear transfer, or nuclear transfer (NT) for short. NT involves removing the haploid nucleus of an egg, inserting the diploid nucleus of a somatic cell, and then chemically or electrically inducing the egg to divide.

Complete genetic identity between a person and self-clone would result from cloning only if a woman were to donate an egg for enucleation, as well as the nucleus from one of her somatic cells to be inserted into that egg. Even though their nuclear DNA would be identical, other progenitor (donor)-clone pairs would not be a perfect genetic match, including any in which the nuclear donor was male. That is because some DNA is extranuclear. This mitochondrial DNA is inherited only from the mother. It constitutes a relatively small percentage of a person's total DNA, but that doesn't make it unimportant.

Further complicating the picture is the phenomenon of epigenesis, or gene expression. Although identical twins have completely identical genes, environmental influences, both before and after birth, can affect the way the genome is read. The more time that monozygotic twins live apart, the older they get, and the more divergent their lifestyles, the greater the epigenetic difference one finds between them.

Those who claim that human clones are fated to not be viable as embryos and fetuses, and hence to die before birth, base their prediction on faulty epigenesis-in particular, the fact that maternal "imprinting" marks are removed by the cloning process.

Epigenetic differences would surely be present between progenitor and clone because their environmental history would necessarily be different, both physically and psychologically. Despite this, identical twins are still the best genetic and biologic analogue available for use in trying to anticipate clone psychology.


Most discussions of the conceivable psychological consequences of cloning have been cursory and begin and end with identical twins. Not those of Dr Segal. In previous publications, she has stated that cloning might have the potential to be beneficial psychologically. She has raised the idea that a progenitor parent might be capable of greater empathy for his or her self-clone than many parents have for their sexually reproduced offspring.

 However, Dr. Segal notes that the identical twin situation does not capture some important aspects of cloning by NT and that we ought to be looking for other "naturally occurring models that mimic essential aspects" of reproductive cloning.

I believe that this issue requires an orientation that is clinical as well as scientific. Yes, it makes sense scientifically to explore other analogues to reproductive cloning, but the Hippocratic dictum, "first, do no harm," also demands it. As part of this, we must try, however imperfectly, to evaluate whether a younger genetic replica of person would risk psychological harm as such. I try to do just this in my book, Clone Being: Exploring the Psychological and Social Dimensions.

 In addition to examining identical twins, this book also lays out other situations that are relevant by analogy to certain aspects of cloning:	   

These analogue situations and phenomena give us a means to both generate and ground inferences regarding clones and cloning. It would be impossible to discuss each of these analogues in the space available here, but I will briefly sketch a few of what I see as the most central psychological issues raised by human cloning. These are sketched in more detail in the Tables, below, and a fuller exposition can be found in the book referred to above.

Table 2: Assisted reproductive technology (ART) analogue

Table 5: Parent-child resemblance analogue

The first 4 analogues, identical twins, ART, the stepchild, and adoption, each provide different ways to explore how the degree of genetic relatedness, as well as resemblance, may affect the parent-child relationship. This issue is crucial to trying to anticipate the relationship of the progenitor parent and clone and of the nonprogenitor parent and the child. In addition, it has implications for the relationship of the rearing parents to one another.

Each of the 8 analogues demonstrates the paramount role of the parent-child relationship in the child's psychosocial development. The genetic relationship between a parent progenitor and clone would be akin to that between an older and a younger twin. However, when the child is a genetic copy of a rearing parent, the social relationship between them would certainly be one of parent and child. Of course, it would be a special sort of parent-child relationship because the self-clone would be a genetic replica of that parent. This by itself might not be problematic, but it would quickly become so if that fact led a parent to erroneously believe himself or herself to be qualified genetically as an expert on the child. That conviction, used as a basis for greater parental authority, would add to other sources of asymmetry intrinsic to any parent-child relationship.

Dr Segal tells us that monozygotic twins are not more likely to suffer from a mental disorder, something we might expect if the individual twin's sense of autonomy and personal identity were threatened by the presence of a genetic duplicate in his or her life. But Segal is  not justified in concluding that the age and other differences between a clone and progenitor would produce even less reason for concern. 

On the contrary, the differential in age, knowledge, power, and dependency between any rearing parent and child are factors at least as potent as any benefit that may result from  close genetic relatedness and resemblance. These asymmetric factors are inherent in any parent-child relationship, and how parents use them has a tremendous impact on their child, for good or ill. When it comes to cloning, the progenitor's knowledge that his self-clone is an exact genetic self-replica would surely accentuate this already vast differential.


In various ways, the stepchild, adoption, parent-child resemblance, and namesake models all bear on the parental wish for self-resemblance in a child. The wish to have a child greatly resembling oneself is likely to motivate some individuals to self-clone. No sexually reproduced child could come close to the degree of self-resemblance that would be expected to be seen in a self-clone.

The wish for self-resemblance in one's child appears to be normal to a degree and can be understood as a consequence of the need for kin identification, a cornerstone of evolutionary theory.

 Research in evolutionary psychology has shown that adults tend to find a child's face most appealing when it has been computer morphed to resemble their own.

One way that pathologically narcissistic patients may damage their children emotionally is by demanding self-resemblance from them.

 It stands to reason that self-cloning would appeal to such individuals, even if it were not the stated primary or even conscious motivation.

Granted, it would be in the genetic "nature" of the clone to resemble his progenitor. However, the "nurture" of the clone would largely determine the extent to which the child becomes clone-like psychologically.


The child-of-the-famous, parent-child resemblance, the "replacement" child, and the namesake analogues are the most relevant by analogy to anticipating expectations of a clone. If the progenitor is a person other than the clone's rearing parent-someone the parents consider ideal, such as a lost loved one-would they expect or even insist that the child be just like that person? Such expectations could be both conscious and unconscious and enacted transferentially.

Crucial to expectations concerning clones is the fallacious assumption that close resemblance or even genetic identity causes or is a sign of personal sameness.

 The expectation that empathy between progenitor and clone would be enhanced may well be an example of this fallacy.

 should be superior between an identical self and other. But even though genes and their expression are vitally important, a person's self and genetic identity are not the same, just as close physical resemblance or bearing an identical name do not make two people the same.

Dr Segal tells us that identical twins tend to feel especially close and attached to one another, but this is not exactly the same as empathy. For the sake of argument, let us suppose that possessing a genome identical to his clone would, in fact, bestow on the progenitor an enhanced ability to understand the child. Would this necessarily be to the child's benefit?

Such parents might be less likely to admit the possibility of error, emulating a common pattern with narcissistic parents. They presume to know what and how their child thinks and feels without ever bothering to find out.

Of course, an individual choosing to self-clone might well be narcissistic to begin with. However, a parent's knowledge that his child is a genetic self-replica might accentuate any parent's propensity to enact narcissistic transferences toward the child. Such transferences are incompatible with parental empathy.

Whatever the case may be, any understanding held with conviction can overwhelm a child, whether it is true or false. And of course, such a conviction itself imposed on the child would not be empathic.

But even superior parental understanding most empathically applied might not be advantageous for the child clone. The child might be better off in the long run with a parent, who, in Winnicott's terminology, is simply "good enough."

A clone's expectations of himself would hinge only partially on knowing that he is a clone-his understanding of which is likely to evolve over time. But even if his clonal status has not been divulged to him, or if he so young that he barely grasps the idea, there is another equally important factor: whether the clone's parents consciously or unconsciously try to shape him to conform to the expectations they have of him as a clone.


In conclusion, psychological problems based on a child's status as a clone would not be a given. However, it might be very hard for a parent to resist inducing psychological "clone-ness" in the child. After all, a desire for a genetic replica of the self or a particular other would probably be part of what would have drawn the parent(s) to cloning in the first place. Parents rearing a clone would be highly likely to perceive and relate to that child as if he were someone else.

That said, it would not be impossible to parent a clone well, and if Dr Segal is right, there could even be some potential advantages. However, the parenting of a clone would present challenges over and above the usual challenges of parenthood. If cloning should ever become another ART, let us hope that those interested in it carefully examine their motives. Perhaps insights gained in psychotherapy might lead them to explore other paths to parenthood and if not, to better manage their transference propensities toward the child.

The prospect of human cloning puts a number of fundamental psychological assumptions and concepts in a new and seemingly alien frame. For this reason, it has the potential to provide fresh perspectives, not only on the issues it raises, but also on the situations and phenomena serving as analogues to it. There is a need for psychological research on these situations and phenomena designed specifically to better anticipate the psychological consequences of cloning. In her Viewpoint, Dr Segal shares some fascinating ideas for a few such studies.

In the meantime, even if the medical risks could be substantially reduced, it would be foolhardy to introduce asexual reproduction as a new ART. Though no single psychological analogue of cloning is thoroughly convincing, taken together they do suggest that a clone would be at increased risk for psychological harm. It would not be in a child's best interest to be linked genetically to only 1 person. Such an exclusive linkage could well put the clone's psychosocial development at risk.

Only in sexual reproduction are genes contributed from two individuals and uniquely recombined in the offspring. This fact may well be the basis for enough, but not too much, parental investment in a child.

Dr Levick is clinical assistant professor of psychiatry at the University of Pennsylvania School of Medicine in Philadelphia and author of Clone Being: Exploring the Psychological and Social Dimensions (Rowman & Littlefield, 2004). He reports no conflict of interest regarding the subject matter of this article.

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The world began to face the prospect of human cloning when the journal Nature published Dolly the sheep's "birth announcement" in the form of a letter authored by Wilmut and colleagues. But despite all the attention given the issue, including two presidential commissions, the psychological consequences of cloning have been little addressed.

Stephen E. Levick, MD

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