Embryo and Fetus: II. Embryo Research

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In previous editions of this encyclopedia, the topic of embryo research was included within the entry on fetal research. However, during the latter part of the twentieth century the issues arising from research involving in vitro fertilized embryos became sharply distinguished from issues in research with already-implanted fetuses. Moreover, new technologies such as the development of embryonic stem cells and the possibility of human cloning raised new ethical concerns in relation to research involving human embryos.

This entry will address the history of human embryo research, public policy on embryo research in the United States and internationally, moral considerations, particularly the debate on the moral status of the human embryo, and the relevance of ethical distinctions that have been proposed, such as the distinction between research use of surplus embryos versus embryos created specifically for research.

The Research Subject

Scientifically the product of conception is called an embryo until eight weeks of gestational age, when the name changes to fetus. However, contemporary discussions of embryo research customarily restrict the term embryo to the earliest stages of human development before implantation in the uterus occurs. This terminology is supported by the U.S. federal regulations on fetal research, which define the fetus as "the product of conception from implantation until delivery," thus excluding non-implanted embryos from the regulations (45 CFR 46.202).

In practical terms the embryo as subject of research is the embryo in the laboratory, generally the result of in vitro fertilization (IVF), but possibly developed by other means, for example, through flushing naturally-fertilized eggs from the fallopian tube, or through somatic cell nuclear transfer (SCNT) of a body cell into an enucleated egg, a type of cloning procedure.

A variety of terms has been proposed for the embryo as subject of research:

the preembryo,

the preimplantation embryo,

the embryo ex utero,

the early embryo.

In this entry the simple term embryo will be used, with the understanding that it refers to the embryo in the laboratory that has not undergone transfer to a woman. Some commentators maintain that only embryos resulting from fertilization of eggs by sperm are properly called embryos. This question will be addressed in later sections when it is relevant.

Early History of Embryo Research

Until the 1990s most research involving human embryos was directed toward improving the chances for pregnancy in laboratory-assisted conception. These investigations, in turn, were based on many years of research with animal models, where virtually all research in the United States has been supported with federal funding. It was hoped that procedures developed in animal studies could later be applied to human reproduction and embryology, especially to the understanding and alleviation of human infertility.

Attempts at laboratory fertilization of human oocytes (precursor eggs) showed some promise as early as 1944 in the work of American obstetrician-gynecologist John Rock and scientist Miriam Menkin. From that time until the birth of the first child conceived through IVF in 1978, various approaches were tried in order to achieve a pregnancy and live birth. The work of Robert Edwards, British reproductive endocrinologist, culminated in the birth of Louise Brown after he collaborated with Patrick Steptoe, an obstetrician who utilized laporoscopy for viewing and recovering a mature ovarian follicle containing an oocyte capable of fertilization.

According to embryologist Jonathan Van Blerkom, most current methods used in laboratory-based treatment of infertility have evolved from those used by Edwards and Steptoe and their predecessors. According to Van Blerkom, this work "established the basic science foundation of clinical IVF" (p. 9). Without these four decades of research on fertilizing oocytes, accompanied by study of the early cleavage and development of fertilized eggs or zygotes, the clinical practice of IVF, which is an almost universally accepted primary treatment for infertility, would not exist.

U.S. Funding and Regulation of Embryo Research

In 1975 the U.S. National Commission for the Protection of Human Subjects recommended guidelines for federal funding of research involving human fetuses, but stipulated that these guidelines did not cover research on IVF or on embryos resulting from IVF. It proposed that an Ethical Advisory Board be appointed to review such protocols, and this recommendation was incorporated into federal regulations. In 1978 an Ethics Advisory Board (EAB) was appointed to recommend a policy on federal funding for research involving IVF.

In its 1979 report the EAB concluded that research on IVF was ethically acceptable for federal funding under these conditions: that all federally funded research is directed toward establishing the safety and efficacy of IVF; all gametes used to develop embryos in research protocols are provided by married couples; and no embryos are preserved in the laboratory beyond fourteen days of development. The EAB's rationale was based on two main points. First, it would be irresponsible to offer clinical IVF without doing the studies necessary to insure its safety and efficacy. Second, given the high rate of embryo loss in natural procreation, a similar rate of loss could be tolerated for the goal of eventually achieving pregnancies and births.

The EAB did not distinguish between embryos created for research purposes and embryos remaining from infertility treatment. In fact, the board implied that at times it might be necessary to create embryos with no intent to transfer them to a woman. For the sake of safety, the results of new types of procedures would have to be studied in the laboratory before the procedures were offered clinically. It would be unethical to transfer to a woman the embryos resulting from unvalidated novel procedures.

The EAB report elicited an outpouring of letters opposing embryo research, and its recommendations were never implemented. When the EAB charter expired in 1980, a subsequent board was not appointed, thus leaving no body to review proposals for federal funding of IVF and embryo research. This situation effectively created a moratorium on federal funding in the United States, though it did not affect research that was privately funded.

Public Policy in Other Countries

It is not possible to review all legislation and policy recommendations throughout the world, but two early initiatives are of particular interest. They come from countries that share a common law tradition with the United States, Australia (Victoria), and the United Kingdom.

AUSTRALIA (VICTORIA). The earliest comprehensive legislation on reproductive technologies was enacted in the State of Victoria, Australia in 1984. The Infertility (Medical Procedures) Act addressed embryo research by prohibiting research that might damage the embryo or make it unfit for implantation. This prohibition appeared to outlaw any IVF or embryo research that was not directed toward benefiting each individual embryo.

In 1986 the review committee established by the act received a proposal for research on the microinjection of a single sperm into an egg. In their application the investigators suggested a novel approach for circumventing the prohibition on embryo research. They proposed to examine the egg after the sperm had penetrated it, but before the genetic contributions of the sperm and egg had fused at the stage known as syngamy. Arguing that fertilization was not completed until syngamy had occurred, researchers claimed that the law did not apply until the time of syngamy, thus giving them approximately twenty-two hours after sperm penetration for conducting their studies.

Since the review committee was uncertain as to whether the 1984 act allowed this interpretation, it recommended that the act be amended to clarify that research was permissible if it ended by the time of syngamy, even if the research destroyed the embryo's potential for implantation. The act was amended according to this recommendation in 1987.

UNITED KINGDOM. The issue of the regulation of reproductive technologies and embryo research was particularly pressing in the United Kingdom because of the publicity given to the birth of Louise Brown in England in 1978. The Warnock Committee was appointed to study the matter, and its 1984 report recommended national regulation of assisted reproduction. It also recommended that research on embryos resulting from IVF be permitted up to the fourteenth day after fertilization, under the jurisdiction of a licensing body.

Based on the Warnock Report, the Human Fertilisation and Embryology Act (HFE Act) of 1990 commissioned a standing body, the Human Fertilisation and Embryology Authority (HFEA), to develop standards for licensing clinical facilities and research protocols, and mechanisms for auditing and oversight. Initially research protocols were restricted to the study of infertility, the causes of congenital diseases, and the detection of gene or chromosome abnormalities in embryos.

Since its establishment in 1991 the HFEA has addressed new types of procedures and research through public consultation processes as well as the advice of experts. If a matter was beyond the scope of authority of the HFEA, it was referred to Parliament. In January 2001 Parliament extended the HFE Act to permit embryo research directed at increasing knowledge about treatments for serious diseases. This provision would allow the HFEA to issue licenses for research on embryonic stem cells, including stem cells derived from blastocysts resulting from somatic cell nuclear replacement (SCNR). However, the Pro-Life Alliance brought a challenge to this provision, arguing that the HFE Act applied only to embryos resulting from the fertilization of eggs by sperm. Despite a Court of Appeal ruling against the Pro-Life Alliance, in June 2002 the House of Lords agreed to hear a final appeal of the case. In March 2003 the House of Lords ruled that the HFE Act applied to all types of embryos, and hence the HFEA had authority over research with embryos created by nuclear transfer as well as embryos resulting from fertilization by sperm.

The U.S. Human Embryo Research Panel

After nearly twenty years of moratorium on federal funding of research involving IVF, the U.S. Congress in 1993 revoked the requirement of EAB review. Through the National Institutes of Health (NIH) Revitalization Act of 1993, Congress explicitly permitted the NIH to fund research on assisted reproductive technologies with the goal of improving the understanding and treatment of infertility.

Since research on IVF includes the study of IVF-fertilized embryos, the research authorized by Congress included research involving human embryos. Recognizing the controversial issues raised by this research, NIH decided to conduct an examination of ethical issues before funding any research proposals. Consequently, the Director of NIH appointed the Human Embryo Research Panel (HERP) to provide advice and recommendations.

In developing its position and recommendations, the panel focused on two distinct sources of guidance: viewpoints on the moral status of the early human embryo, and ethical standards governing research involving human subjects. It considered a wide range of possible views on the moral status of the embryo, from the position that full human personhood is attained at fertilization, to the argument that personhood requires self-consciousness and is not attained until after birth. In the end, all nineteen members of the panel agreed to the following statement:

Although the preimplantation embryo warrants serious moral consideration as a developing form of human life, it does not have the same moral status as an infant or child. (Human Embryo Research Panel, p. x)

This conclusion implied that the preimplantation embryo is not a full human subject and thus is not a fully protectable human being. As a result, some research that might be destructive to the embryo could be acceptable for federal funding. But the panel also asserted that the human embryo "warrants serious moral consideration," requiring that it be treated differently from mere human cells or animal embryos. The panel proposed restrictions on embryo research that would express such moral consideration, for example, that human embryos be used in research only as a last resort, that the number of embryos used be carefully limited, and that embryos not be allowed to develop longer than required by a specific research protocol, and in no case longer than fourteen days of development.

In applying the ethical standards governing research involving human subjects, panel members invoked the criteria used by Institutional Review Boards (IRBs) in approving research protocols. Donors of eggs, sperm, or embryos were to be informed of the specific goals, procedures, and risks of research projects. Risks to donors, particularly egg donors, were to be minimized. Eggs for research could be donated only by women who were undergoing diagnostic or therapeutic procedures where egg retrieval would present little additional risk.

The most controversial issue facing the panel was the question of whether human oocytes could be fertilized solely for research purposes. The panel decided to allow such fertilization only under very special circumstances, most particularly, if certain research by its very nature could not otherwise be conducted. For example, research on the laboratory maturation of human oocytes, which could eliminate the need for egg donors as well as infertile women to be subjected to high levels of hormonal stimulation, requires study as to whether such oocytes can be successfully fertilized.

The panel's limited acceptance of the fertilization of oocytes for research purposes aroused strong criticism, and President Bill Clinton immediately announced his opposition.

The Aftermath in the United States and Beyond

Despite President Clinton's directive that NIH not fund research involving the creation of embryos, most types of research on IVF and human embryos were still eligible for federal funding. However, in its next appropriations bill Congress reversed its previous stance and prohibited NIH from funding any research that might involve damaging or destroying human embryos. In 2003 this prohibition was still in effect.

During the 1990s scientific advances raised new questions regarding research with human embryos. In 1998 the first embryonic stem cell lines were developed from the inner cell mass of human blastocysts, and at the same time, similar stem cell lines were produced from the germ cell tissue of aborted fetuses. Deriving stem cells from blastocysts was clearly prohibited for federal funding. However, the derivation of stem cells from the tissue of aborted fetuses was eligible for federal funding under previous legislation (U.S. Public Law 103–43, Manier).

Another discovery was the successful cloning of a variety of nonhuman animals from adult cells, beginning with the cloning of the sheep Dolly in 1997. Research on human cloning arguably involves research on human embryos. These embryos are produced by transfer of somatic cell nuclei into enucleated oocytes, rather than through fertilization of eggs by sperm, yet their development and potential appear to be similar to those of fertilized eggs. Thus cloning research raises similar ethical questions.

The day after the announcement of the cloning of Dolly, President Clinton instructed the National Bioethics Advisory Commission (NBAC) to undertake a thorough review of the technology and to report within ninety days. Given this short deadline, it is understandable that NBAC had to focus on issues specific to the cloning process. In particular, NBAC decided to "not revisit … the issues surrounding embryo research," since the topic had "recently received careful attention by a National Institutes of Health panel, the Administration, and Congress" (Shapiro).

In contrast, when the President's Council on Bioethics appointed by President George W. Bush issued its report on cloning in 2002, it called for a broader debate on the entire topic of human embryo research. The ten-member majority of the council wanted cloning discussed "in the proper context of embryo research in general and not just that of cloning" (p. 133). Both the majority and minority reports call attention to the fact that human embryo research of all types remains essentially unregulated in the private sector, with the minority noting that "it seems inappropriate to halt promising embryo research in one arena (cloned embryos) while it proceeds essentially unregulated in others" (p. 143).

In the United States, public policy at the national level is focused on what types of research are eligible for public funding. There is essentially no regulation of research in the private sector. This situation contrasts sharply with that of most other countries, where laws apply to all research, regardless of the funding source.

As of April 2003, Germany, Austria, and Ireland prohibit embryo research unless intended to benefit the individual embryo subject. Germany does allow some importation of established stem cell lines for research. France prohibits any embryo research that would harm the embryo. However, in January 2002 the French assembly passed a bill that, if enacted, would permit research using surplus embryos originally created for reproductive purposes. Sweden allows research on surplus embryos up to day fourteen, including research on deriving stem cell lines. Creating IVF embryos solely for research is prohibited, but creating embryos through nuclear transfer is not mentioned in Swedish law and thus has an uncertain legal status. The United Kingdom arguably has the most permissive policies on embryo research within the European Union. It explicitly sanctions the granting of licenses to create embryos, including cloned embryos, for specific research projects.

Because of the diverse views and policies of its member states, the European Union has taken an intermediate position, providing support for research on surplus embryos in countries where that is permitted, but discouraging the creation of embryos for research. In April 2003 the European parliament voted for a ban on cloning or otherwise creating embryos for stem cell research. However, this decision becomes law only if approved by all fifteen member states of the European Union.

In May 2002 the Assisted Human Reproduction Act was introduced into the Canadian Parliament. The act prohibits the creation of a human clone for any purpose. It also prohibits the creation of an IVF embryo for research purposes with the exception of "improving or providing instruction in assisted reproduction procedures." In April 2003 the bill was in its third reading in the House of Commons.

In some non-Western countries, embryo research is proceeding with few restrictions. Chinese laboratories are forging ahead with cloning research to develop stem cells. Though Chinese scientists have been slow to publish their work, they may well be ahead of their Western counterparts (Leggett and Regalado). India has developed a number of internationally recognized stem cell lines, and scientists are developing additional lines. Dr. Firuza Parikh, Director of Reliance Life Sciences in Bombay, links their success to the absence of cultural and political opposition to embryo research (Lakshmi).

The Moral Status of the Early Embryo

In contrast to China and India, most Western countries are deeply divided over ethical issues related to embryo research. Does the embryo merit full protectability from the moment of fertilization, or does it gradually attain full protectability as it moves through a series of developmental stages? If fertilization is not the point of greatest moral significance, is there some later developmental marker beyond which embryo research ought not be conducted?

FERTILIZATION. Fertilization of egg by sperm marks the initiation of a new and unique genotype, that of a human being distinct from either of its progenitors. The zygote or fertilized egg not only contains the plan or blueprint for a new human being, but it has the potential within itself to develop into that human being.

Based on these facts, many would argue that the zygote is a full human being from the moment it comes into existence. This view would preclude any research that might be harmful or destructive to an embryo, unless intended to be therapeutic for that embryo or to improve its chances for implantation. This position has received able defense in contemporary terms by opponents of embryo research (McCarthy and Moraczewski).

It is possible to hold this position while acknowledging that fertilization is a process rather than an instantaneous event, and hence that the new human life begins only when the process of fertilization is completed. At least two possible candidates marking the completion of fertilization have been suggested. The first is the time of syngamy, when the chromosomes from the male and female gametes unite to form the genotype of the embryo. Since syngamy is not completed until about twenty-four hours after the sperm penetrates the egg, this view would allow some study of the early development of the embryo.

A second proposal maintains that the embryo does not begin its life as a new human being until the regulation of its development switches from oocyte genes to embryonic genes. In 1988 Peter Braude and colleagues showed that this occurs at the six- to eight-cell stage, approximately two days after penetration of egg by sperm. Arguably the embryo begins its own life distinct from that of the oocyte at the time that its own internal regulatory mechanism begins to function. This interpretation would allow investigation of questions such as why a large proportion of embryos are arrested in their development during the earliest cell divisions (Van Blerkom).

Such variant views of the process of fertilization do not counter the claim that the human being begins its life at fertilization. Rather, they provide differing interpretations as to what constitutes fertilization, under the assumption that the formation or activation of the unique genotype of the new organism is the crucial event.

IMPLANTATION. Implantation is the process by which the embryo imbeds itself in the uterine wall and begins to take nourishment from the woman, thus marking the beginning of pregnancy. It is at this time that the U.S. federal regulations define the product of conception as a fetus, and the research regulations begin to apply (45 CFR 46.201–207).

From a moral point of view, some have argued that the IVF embryo lacks the potential to develop into a human being as long as it is simply maintained in culture in the laboratory. Only those embryos that are transferred to women and that implant successfully acquire the potential for development. This type of argument has been utilized by politicians like U.S. Senator Orrin Hatch, who support some forms of embryo research while they take pro-life positions in relation to abortion. In his testimony to a Congressional subcommittee in July 2001, Hatch stated, "I believe that a human's life begins in the womb, not in a petri dish or refrigerator."

This view can be linked to a philosophic distinction between possible persons, entities that could possibly develop into persons if certain actions were taken with respect to them, and potential persons, entities that will develop into persons in the normal course of events unless something happens or is done to interrupt that development. The embryo in the laboratory or freezer is a possible person that might develop into a person if action were taken to transfer it to a uterus. The already-implanted embryo or fetus is a potential person that, under normal circumstances, will continue to develop into a person. Proponents of this distinction argue that while we may have a moral obligation not to interfere with the development of a potential person, we do not have a similar obligation to bring every possible person into existence (Singer and Dawson; Tauer 1997a).

PRIMITIVE STREAK. In the late twentieth century, scholars were faced with biological data about early embryonic development that led to new perspectives on the ontological and moral status of the early embryo. Particularly within the Catholic tradition, writers such as Norman Ford, John Mahoney, Richard McCormick, and Karl Rahner developed arguments questioning whether the zygote or early embryo is a full human being or human person. Their arguments appealed to the following points:

  1. Twinning of the embryo is possible until implantation, and at least through the morula stage, several embryos may aggregate (recombine) to form one embryo. Thus the embryo lacks developmental individuation at this early stage. Philosophic arguments that rely on the continuity of personal identity and religious arguments based on ensoulment must deal with the phenomena of twinning and recombination, which occur naturally and can also be induced scientifically.
  2. Until the blastocyst stage at approximately five days after fertilization, the cells of the embryo are totipotent or completely undifferentiated. Each cell has the capacity to differentiate into any of the cell or tissue types of the fetus, or more likely, not to become part of the fetus at all but rather to form placental and other extra-embryonic tissues. The early embryo is a collection of undifferentiated cells rather than an organized individual.
  3. At approximately fourteen days after fertilization, the primitive streak appears, the groove along the midline of the embryonic disk that establishes in the embryo its cranio-caudal (head-to-tail) and left-right axes. The primitive streak marks the beginning of the differentiation of cells into the various tissues and organs of the human body, and thus initiates the development of the embryo proper (the cells that will become the fetus) as an organized, unified entity. The primitive streak is also the precursor of the neural system.
  4. In normal procreation, during the period between fertilization and the completion of implantation a large proportion of embryos (generally estimated at over 50%) are discarded naturally. Karl Rahner argues that it is implausible that such a large number of human beings could come into existence and disappear without anyone's knowing about it. Others have argued that given nature's prodigality with human embryos, it ought to be morally acceptable to allow similar types of embryonic losses in research as part of the effort to achieve healthy pregnancies.

These sorts of arguments have been utilized in public policy debates since 1978, and the appearance of the primitive streak has come to be accepted internationally as a marker carrying moral significance. The prohibition of embryo research after fourteen days of development is almost universally accepted.

Opponents of embryo research have responded to claims that the early embryo is not yet a full human being. These commentators find arguments based on twinning and recombination, totipotency of cells, and embryo loss to be unpersuasive (Ashley; Ashley and Moraczewski; Mirkes). In its 2002 report on cloning, the majority members of the U.S. President's Council on Bioethics questioned the significance of the primitive streak as a moral marker, stating:

Because the embryo's human and individual genetic identity is present from the start, nothing that happens later …—at fourteen days or any other time—is responsible for suddenly conferring a novel human individuality or identity. (p. 97)

GASTRULATION AND NEURULATION. Some persons regard the initiation of the neural system or the presence of brain activity to be the most significant marker for the beginning of the life of a human being. This view is based on the belief that the brain is the essential organ underlying our specifically human capacities. It also represents an effort to identify a criterion at the beginning of human life that is analogous to the criterion of whole-brain death marking the end of life. For those who regard the presence of sentience as a necessary condition for personhood, the neural system is significant since sentience is impossible in the absence of any neural structures.

While there is debate as to the stage at which brain activity first occurs, it is certain that there is no brain activity before fourteen days of gestational age. The emergence of the primitive streak marks the very beginning of the development of the nervous system. If the presence of neural structures is the significant criterion for the beginning of a human life, then it might be permissible to extend embryo research slightly beyond fourteen days of development.

Several possible cut-off points have been suggested. By the completion of gastrulation at about seventeen days, the three germ layers of the embryo are in place, with cells of each layer committed to forming tissues and organs of one of three types. Subsequent neural development leads to the beginning of closure of the neural tube around twenty-one days, with the primitive nervous system in place by the completion of neurulation around twenty-eight days.

However, given the widespread consensus that fourteen days of gestational age is a morally defensible boundary for embryo research, there has been limited discussion of extending research to a later embryonic stage.

Other Moral Considerations

Those who believe that the human embryo is a fully protectable human being have no choice but to oppose embryo research that could not ethically be performed on infants or children. But those who maintain that the early embryo is not yet a full human being, still have to determine how that embryo ought to be treated.

Some have proposed severely restrictive criteria for embryo research. Norman Ford, after providing painstaking arguments to support the conclusion that the embryo cannot be a human individual until fourteen days after fertilization, acknowledges that he could be wrong. In his view, the Catholic Church is right to insist on the principle that "human embryos should be treated as persons," even if they may not be (2001, p. 160). In other words, as long as there is any degree of uncertainty regarding the moral status of the embryo, it must be absolutely inviolate.

A more commonly held view is that the human embryo has an intermediate sort of moral status. While it is not a fully protectable human being, it is not merely cells or tissue. Proponents of this view are generally willing to permit some embryo research with restrictions that acknowledge that the embryo is nascent human life or a developing form of human life. Our ethical obligation toward the embryo is often characterized as respect or profound respect.

Proponents as well as opponents of embryo research have questioned the concept of respect as a guide for human embryo research. John Robertson, an advocate of scientific freedom with respect to embryo research, believes the notion of respect carries mainly symbolic significance. Hence its practical ramifications are vague, potentially allowing a wide range of types of research. Daniel Callahan, in an essay opposing most embryo research, wonders how one shows respect for a living being while intending to end its life and future potential, even if done for a good purpose such as research on infertility or disease.

In an effort to express respect for the special status of the human embryo, public policy bodies have stipulated conditions for embryo research that are considerably more restrictive than policies on research with human cells or animal embryos. For example, research must have important scientific or medical goals and may involve human embryos only when the research cannot be conducted in any other way. Research projects should be restricted to the smallest number of embryos that is feasible, and for the shortest possible time period. Careful records and security must be utilized to ensure that no embryos are diverted for unapproved purposes and that none are sold.

Bringing Embryos into Existence for Research

One of the most contentious issues in embryo ethics is the question of whether it is ever justifiable to bring human embryos into existence specifically for research purposes. Many would argue that research use of surplus embryos remaining after the completion of infertility treatment is ethically acceptable, since these embryos are destined to be destroyed in any case. At the same time, they may hold that the development of embryos for research purposes, so-called research embryos, is not morally justified.

The development of embryos for research purposes has been characterized as a novel practice that requires particular justification. Referring to embryos created through nuclear cell transfer, the President's Council on Bioethics in 2002 claimed that such research creation of embryos would constitute crossing a "major moral boundary" (p. 132). Yet decades of research on human IVF beginning in the 1930s required investigation of various methods of laboratory fertilization, followed by study of cleaving fertilized eggs to determine their normality before transfer to a woman was even considered (Soupart and Strong; Edwards and Steptoe).

Commentators agree that there is no ontological or intrinsic distinction between surplus embryos remaining after infertility treatment and research embryos developed specifically for study. Arguments that support a moral distinction must identify other morally relevant factors. The concept of respect is often invoked, as is the notion of intent.

Respect for the special status of the embryo seems to require that embryos be treated as entities of intrinsic value. When embryos are created purely for research purposes, they become instruments for purposes that have nothing to do with the embryos themselves. In Kantian terms, the embryos are used solely as means for the welfare of others rather than as ends in themselves. The practice of creating research embryos thus results in treating embryos as commodities, equivalent to mere cells or tissues.

In contrast, the intent to procreate justifies the development of embryos in the laboratory. Even when a large number of eggs is fertilized in an IVF procedure, each fertilized egg has an equal chance of being transferred to a woman and developing into a human being. Thus each zygote is equally respected for its procreative potential.

It is only because some of the embryos cannot be transferred (because of the decision of the progenitors, or because there simply are too many of them) that they become surplus embryos and are destined for destruction. It is arguably permissible to derive some good from the inevitable destruction of these embryos by using them in research. In doing so, one may be said to be choosing the lesser evil.

These arguments have been countered by a number of considerations.

It may be true that respect for the special status of the human embryo requires that it be treated differently from mere human tissue. But the concept of respect is vague and undetermined, so that a wide range of concrete interpretations is plausible. The claim that respect precludes all creation of research embryos gives heavy weight to one interpretation of the concept at the expense of any countervailing considerations. Research projects that include the development of embryos may promise significant benefits for relieving the suffering of living human beings. These benefits could outweigh a particular interpretation of respect.

While procreative intent may justify the creation of embryos in the laboratory, it is plausible that other sorts of purposes could provide equally valid justifications. The treatment of infertility, an elective medical procedure, may even hold lesser moral significance than the development of cures for life-threatening or significantly disabling diseases and trauma outcomes. Hence such goals may also justify the creation of embryos.

Moreover, surplus embryos do not appear purely by chance. Clinicians frequently make a decision to fertilize large numbers of eggs in order to optimize the chances of establishing a pregnancy. The initial intent is not to give every zygote the opportunity for implantation, but to achieve one or more pregnancies and births, as desired by the progenitors. A later decision to direct unused embryos to research cannot be justified by the principle of the lesser evil, since the existence of surplus embryos should have been anticipated. This situation was deliberately caused and could have been avoided. Thus it is invalid to invoke the principle of the lesser evil to justify use of surplus embryos in research, while maintaining that any creation of research embryos is prohibited.


A potentially non-controversial process for developing morulas and blastocysts for research is the activation of oocytes without use of sperm or transfer of somatic cell nuclei. Such activation can be achieved through electrostimulation or chemicals in a process called parthenogenesis. The resulting cleaving eggs, called parthenotes, may develop much like normal embryos at least to the blastocyst stage. Although no human parthenotes have progressed this far, in February 2002 scientists announced that they had developed monkey parthenote blastocysts and established stable stem cell lines from them (Cibelli, et al.).

Scientists believe "there is a profound and intrinsic biological barrier that prevents mammalian parthenotes from developing to advanced fetal stages" (Human Embryo Research Panel, p. 20). On this assumption, parthenogenic morulas or blastocysts lack the intrinsic potential to become human beings. If this potential is a defining aspect of the human embryo and the basis for its special moral status, then human parthenotes are not human embryos and should not arouse the same sorts of moral concerns. Thus they may offer an attractive alternative for research.

carol a. tauer

SEE ALSO: Abortion: Medical Perspectives; Children: Healthcare and Research Issues; Cloning; Feminism; Fetal Research; Infants; Infanticide; Maternal-Fetal Relationship; Moral Status; Reproductive Technologies: Ethical Issues; Research Policy: Risk and Vulnerable Groups;Research, Unethical; and other Embryo and Fetus subentries


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