All of the research discussed in this entry involves women and men, as well as human embryos and fetuses. When implantation is a necessary condition for the research, as in the case of most fetal research, the fetus is implanted in the uterus of a woman. For all of the research considered in the entry, the oocytes (eggs) of at least one woman are required; in cases involving in vitro fertilization (IVF), the oocyte retrieval process can be onerous for the woman involved. In addition, sperm from at least one man are required for fertilization. Finally when research is conducted on the developing fetus, interventions also directly impact and take place through the body of the pregnant woman. For reasons of brevity, this entry focuses primary attention on the developing human embryo and fetus. However recognition of the inextricable connection between the fetus or embryo and the woman and man who provide the gametes that give rise to it or to the woman in whom gestation occurs is critical to ethical discourse, and is explicity discussed where possible.
Four major types of research will be analyzed in this entry:
- research on preimplantation embryos;
- research on unimplanted embryos and fetuses beyond the fourteenth day of development;
- research on implanted embryos and fetuses; and
- research on aborted, live embryos and fetuses.
The topic of research on living tissue derived from fetal remains is discussed in a separate entry.
Preimplantation Embryo Research
The human preimplantation embryo can be defined as the developing organism from the time of fertilization to approximately the fourteenth day after fertilization, assuming a normal rate of development. The major preimplantation stages in human and other mammalian embryos are usually distinguished by such names as zygote, morula, and blastocyst. By the end of fourteen days the early human embryo has, except in rare cases, lost the capacity to divide into two individuals; it has also begun to exhibit a longitudinal axis that forms the template for the spinal column, an axis called the primitive streak (McLaren; Dawson, 1990a).
Preimplantation embryo research generally requires the associated procedure of IVF (although it would in principle be possible to retrieve an early embryo by flushing it from the uterus of a woman following in vivo fertilization of an ovum). Thus the question of research on preimplantation embryos did not arise until IVF techniques had been developed and validated, first in laboratory animals, then in humans. In 1959 M. C. Chang of the Worcester Foundation in Massachusetts was the first scientist to demonstrate unambiguously the fertilization of nonhuman mammalian oocytes in vitro. Chang's success was followed in 1969 by the first confirmed report of IVF with human gametes by three British researchers (Edwards et al.). Only nine years later the first human birth after IVF—the infant's name was Louise Brown—was reported by members of the same British research team (Steptoe and Edwards).
Given that IVF is required for preimplantation embryo research, the risks to the woman of ovarian stimulation and oocyte retrieval are relevant to the discussion. Ovarian stimulation with injectable gonadotropins has been associated in some studies with an increased risk of ovarian tumors (Harris et al.), though the association is controversial. In addition gonadotropins are associated with a risk of ovarian hyperstimulation syndrome, which is associated with ovarian enlargement, massive fluid and electrolyte imbalances, renal insufficiency, and in rare cases thromoembolism and death.
There are two major contexts for research on preimplantation embryos. The first is one in which the transfer of the embryo into the uterus of a woman (or perhaps, in the future, into a device that can support full-term fetal development) is planned. In the second context, no embryo transfer is envisioned and, accordingly, the death of the embryo or later fetus at a stage before viability is intended. These two research contexts raise somewhat different ethical issues.
RESEARCH FOLLOWED BY EMBRYO TRANSFER. In the years preceding the birth of Louise Brown in 1978, researchers devoted substantial attention to improving the prospects for successful IVF and embryo transfer. This research focused on methods for maturing oocytes, facilitating fertilization, and culturing or cryopreserving early embryos (Biggers). During the 1990s, researchers continued this type of research. New methods for assisting fertilization have been devised, including the drilling of a small hole in the outer shell of an oocyte or the injection of a sperm directly into an oocyte, a process known as intracytoplasmic sperm injection (ICSI) (Van Steirteghem). Similarly researchers have developed methods for removing one or two cells from an eight- or sixteen-cell embryo in order to perform preimplantation diagnosis of genetic or chromosomal abnormalities (Edwards, 1993). These techniques are performed so that only embryos without genetic abnormalities are transferred to the uterus, while affected embryos are discarded. In the twenty-first century, one can anticipate research that attempts to prevent the later development of a genetic disease (for example, cystic fibrosis) by treating an individual at the embryonic stage of life. If successful this kind of disease prevention by means of gene modification would be likely to affect all of the cells of the person, including his or her reproductive cells (Wivel and Walters).
The ethical issues that arise with preimplantation embryo research when embryo transfer is planned are at least analogous to those that arise with fetal research in anticipation of birth, with research on infants, and with research on children. That is, one attempts to perform a careful analysis of the probable benefits and harms of the research to the individual and to others; one seeks an appropriate decision maker, usually a genetic parent or a guardian, who can represent the best interests of the potential research subject; and one looks for a disinterested mechanism for prior ethical review of the proposed research. This kind of embryo research, in which the research procedures are often designated therapeutic or beneficial, is generally approved by commentators on the ethics of such research, even if they diverge widely in their attitudes toward IVF, the moral status of preimplantation embryos, and abortion (see, e.g., Ramsey, 1970; Catholic Church; Singer et al.).
RESEARCH NOT FOLLOWED BY EMBRYO TRANSFER. Research in this context may be proposed for a variety of reasons. The goal of the research may be to assess the safety and efficacy of clinical practices, for example, IVF or the use of contraceptive vaccines. Alternatively the goal may be epidemiological, for example, to estimate the frequency of chromosomal abnormalities in early human embryos. Another goal that has gained significant national and international attention is the use of embryos for the creation of stem cells (Thompson et al.). Stem cells are a unique type of cell that have the potential to mature into cells of a particular type (e.g., heart, blood, muscle, or brain cells). This versatility has been thought to hold significant scientific and therapeutic promise for treatment of such diseases as Alzheimer's, heart disease or kidney failure; furthermore, these cells may be essential to understanding early stages of human development. Finally in other cases research on embryos may have little reference to clinical medicine or human pathology. That is, research with preimplantation embryos may be much more basic, seeking to compare early development in various species of mammals or to explore the limits of embryo fusion or hybrid creation among different species.
Two distinct ethical questions have received primary attention in the international bioethics debate about preimplantation embryo research without embryo transfer. The first question is: Is research on such embryos morally permissible if it is not intended to benefit the embryos themselves? If the answer to the first question is negative, the second question is irrelevant. However, if the answer to the first question is affirmative, there remains a second question: Is it morally permissible to fertilize human oocytes for the sole purpose of performing research on the resulting embryos and in the absence of any intention to transfer the embryos for further development?
In their responses to the first question, proponents of nonbeneficial (to the embryos) research procedures adduce several arguments. First the research may produce benefits, either for clinical practice or in terms of basic knowledge, that are not attainable by any other means (U.S. Department of Health, Education and Welfare [HEW]; Warnock; Ethics Committee of the American Fertility Society; Robertson; National Bioethics Advisory Committee [NBAC]). One variant of this argument asserts that it is morally irresponsible to introduce new techniques (for example, cryopreservation of embryos) into clinical practice without first performing extensive laboratory studies of the technique (International Society of Law and Technology [ISLAT] Working Group).
Second, proponents of preimplantation embryo research note that the biological individuality of the embryo is not firmly established until approximately fourteen (or perhaps twenty-one) days after fertilization. Before that time twinning can occur, or two embryos can fuse into a single new embryo called a chimera (Hellegers; Dawson, 1987; Grobstein). If developmental individuality does not occur until after the preimplantation stage, research proponents argue, the preimplantation embryo is not protectable as a unique human being.
Third, proponents of research cite the apparently high embryo loss rate that occurs in natural human reproduction. The most reliable estimates are that approximately 50 percent of the human eggs that are fertilized either fail to develop or die within two weeks after fertilization occurs (Chard). To this factual evidence is added the metaphysical assertion that entities with such a high rate of natural death within two weeks of coming into being cannot be morally significant at this early stage of their existence. Proponents of embryo research may acknowledge that adult persons have some moral obligations toward early embryos, but these obligations are viewed as relatively weak and are thought to be outweighed by, for example, substantial clinical benefits to many future patients (NBAC).
Opponents of preimplantation embryo research have replies to these arguments and adduce other arguments of their own. In response to the first argument of proponents, the opponents assert that the end of desirable clinical consequences does not justify the means of performing research that seriously damages or destroys the embryo. To the consequential argument of proponents, conservatives may counterpose a consequential argument of their own, namely, that negative consequences will result from research on early embryos. For example researchers may become desensitized to the value of human life, or bizarre humannonhuman hybrids may be produced in the laboratory (Catholic Church, Dawson, 1990b).
The second and third arguments of the proponents are viewed as mere descriptions of natural phenomena that carry no particular moral weight. Twinning, recombination, and embryo loss, if they occur naturally and are beyond human control, are in this view no more morally relevant than other natural evils like earthquakes or volcanic eruptions. For their part, opponents put forward two additional arguments. First, the genotype of a new individual is firmly established at the time when the pronuclei from the sperm cell and the ovum fuse. This fusion, sometimes called syngamy, occurs at the conclusion of fertilization. Thus from a genetic standpoint, a new individual exists from syngamy forward. Second, opponents of preimplantation embryo research often adduce the potentiality argument: that the early embryo contains within itself all of the genetic instructions necessary for the development of a fetus, an infant, and an adult, provided only that the embryo is placed in an environment that will nurture its further development. Therefore the person that the early embryo may one day become should be respected in an anticipatory way even at the early stages of development, when it lacks many of the characteristics of persons in the full sense.
Proponents of research do not deny that a new genotype is established at the time of fertilization. They simply point to other factual considerations that are in their view more relevant to moral judgments about the acceptability of embryo research. In response to the potentiality argument, research proponents note that a single sperm cell and a single oocyte have the potential to become an embryo, yet opponents of embryo research do not accord special moral status to reproductive cells. Further only a few cells of the preimplantation embryo develop into the embryo proper; the rest become the placenta, the amniotic sac, and the chorionic villi (McLaren). Finally with the advent of cloning technology (the creation of an embryo from a single somatic cell), a single somatic (i.e., skin, breast, or other) cell theoretically has the potential to become an embryo, and it would be impossible to accord special moral status to every somatic cell in a human's body. In other words potentiality is a continuous notion, or a matter of degree, not an all-or-nothing concept (Singer and Dawson).
Among proponents of research on preimplantation embryos there is a division of opinion on the second question noted above—whether the creation of human embryos specifically for research purposes is morally permissible. Proponents of the conservative answer to this question argue that only embryos left over from the clinical practice of IVF and embryo transfer should be used in research (Steinbock). Such embryos might include those selected out when the number of embryos available for transfer exceeds a number that is considered safe for the woman (between two and five, depending on patient age and other prognostic factors (American Society for Reproductive Medicine [ASRM]). Leftover or surplus embryos might also become available in the context of cryopreservation, if a couple completes its desired family size or if both genetic parents die in an accident while some embryos remain in frozen storage.
The principal argument of conservatives on the deliberatecreation question is a Kantian argument against using early human embryos merely as means. In the opinion of conservatives, creating embryos with the prior intent of destroying them at an early stage of development is incompatible with the respect that should be accorded to human embryos. Conservatives can accept the use of leftover embryos for research because there was at least at one time an intention to transfer the preimplantation embryos to the uterus of a woman, where they could develop into viable fetuses. In their view the research use of such spare embryos is a morally acceptable alternative to donation or discard (Steinbock). The primary argument of those who do not object to creating embryos for research is a composite. Proponents of this view argue, first, that our moral obligations to early human embryos are relatively weak. Further proponents of the liberal view note that good research design may require either a larger number of embryos than the clinical context can provide or unselected embryos rather than those that have been rejected for embryo transfer, perhaps because they are malformed or slow in developing (Ethics Committee of the American Fertility Society). Indeed while estimates are that approximately 400,000 cryopreserved embryos are in storage, only 2.8 percent of these are available for research (Hoffman et al.).
PRACTICE VS. ETHICS. In the 1990s international practice and ethical opinion regarding human embryo research diverged sharply. One polar position in practice was that of the United Kingdom, where research on preimplantation embryos was conducted in numerous laboratories under the supervision of voluntary and (later) statutory licensing authorities (United Kingdom, 1992). At the other pole was Germany, which prohibited the fertilization of ova for the practice of research, as well as any research that was likely to destroy or damage the embryo. In the United States, embryo research was legal though practically limited due to a legislative prohibition of federal funding for: (1) any research involving the creation of a human embryo for research purposes; or (2) any research in which a human embryo is destroyed, discarded, or knowingly subjected to risk of injury or death. This prohibition has been implemented yearly through a provision included in Congressional appropriations for the Department of Health and Human Services (DHHS) since 1996 (P.L. 107–116 ).
Ethics advisory bodies have been far from unanimous in their evaluations of research involving preimplantation embryos. The earliest report on this topic, produced by the Ethics Advisory Board in 1979 for HEW, judged embryo research to be ethically acceptable if it was designed primarily to "assess the safety and efficacy of embryo transfer" (p.106). During the 1980s and early 1990s, there emerged three general positions among such advisory bodies. Several Australian committees rejected the idea of any human embryo research. A few Australian committees and most of the committees based in continental Europe approved embryo research but rejected the deliberate creation of embryos for research purposes. In the Netherlands, the United Kingdom, Canada, and the United States, advisory committees tended to approve both human embryo research and the creation of embryos for research (Walters; National Institutes of Health [NIH]).
In the late 1990s and early 2000s, reports of stem cell derivation from human embryos (Thompson et al.) prompted reexamination of ethics and policy regarding embryo research (Green). International practice and ethical positions remain polarized. In 1999 the NBAC issued a report and recommendations that federal agencies should fund research on embryos left over after IVF for derivation of stem cells but not research involving embryos created solely for research purposes. Despite this recommendation, in 2001, the Bush administration decided to allow federal funding only for research on existing cell lines. In contrast the Human Fertilisation and Embryology Authority (HFEA) in the United Kingdom has continued to permit and license human embryo research and the creation of embryos for research but with enhanced guidelines specific to the derivation and use of stem cells.
Research on Unimplanted Embryos and Fetuses Beyond the Fourteenth Day of Development
The developing human organism is technically called an embryo during the first eight weeks following fertilization. It is called a fetus for the remainder of its development. In this section, prolonged in vitro culture of embryos and fetuses will be evaluated.
Prolonged embryo culture has been undertaken in several species of nonhuman mammals, especially rats and mice. In the early years of research, embryos at various stages of development were removed (or explanted) from the uteri of pregnant females and sustained in various kinds of laboratory devices that delivered oxygen and nutrients (New). More recently unimplanted mouse and cattle embryos have been sustained in culture to developmental stages more complex than those attained by preimplantation human embryos (Chen and Hsu; Thomas and Seidel).
As of 2003 no researchers are proposing to perform studies of either of these types with human embryos. The explantation mode of research will probably not be undertaken in humans because of the risks to the pregnant woman and because the need is questionable. However sustained culture of human embryos after IVF would in principle be possible. It is not clear whether the current lack of proposals to culture embryos in vitro beyond fourteen days is based on technical, ethical, or financial (given the bans on funding for embryo research) considerations. The longest well-documented periods for human embryo culture are eight days and thirteen days (Fishel et al.). Possible rationales for extending embryo culture beyond fourteen days could include studying differentiation, the anatomy and physiology of the embryo, the implantation process, or the effect of drugs or radiation on the developing embryo (Karp; Edwards, 1989; Sass).
There has been relatively little ethical discussion of embryo research beyond fourteen days. Most advisory committees have simply accepted the fourteen-day limit without extensive discussion. In the case of the Warnock Committee report from the United Kingdom, this limit was said to be appropriate because it correlates with the appearance of the primitive streak in the embryo (Warnock, 1984). The primitive streak is the first indication of the embryo's body axis, the last opportunity for twinning to occur, and a point before sentience is attained. Several commentators have suggested that the justification for the fourteen-day limit is relatively weak and have proposed extending the limit for in vitro human embryo research to approximately twenty-eight days (Edwards, 1989; Kuhse and Singer).
If embryo culture methods improve sufficiently, it may one day be possible to sustain either a nonhuman or a human embryo and fetus in vitro for an extended period, or even through an entire gestation. The technological support system that sustains such development will probably be called an artificial placenta. If prolonged embryo culture is employed with human embryos and fetuses, decisions will be required about whether to sustain development to the point of viability. At some point a transition will undoubtedly be made from laboratory research designed to test the technical feasibility of long-term culture to an actual attempt to produce a human child by means of ectogenesis (extrauterine development) (Kass; Fletcher; Karp; Walters).
Research on Implanted Embryos and Fetuses
The ethical questions that surround research on implanted embryos and on implanted fetuses are virtually identical, except for the different stages of development involved. This continuity in biological development and similarity in ethical analysis is so striking that both the U.S. National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research (U.S. Commission for the Protection of Human Subjects) and the British Polkinghorne Committee employed the term fetus to refer to the developing entity from the time of implantation through the whole of gestation. In the following discussion the word fetus and its derivatives will be employed to refer to the embryo or fetus from the time of implantation in the uterus of a woman through the point at which physical separation from the woman occurs.
As in the case of preimplantation embryo research, one can distinguish two major contexts for fetal research. The first is one in which further development and delivery of an infant are anticipated. The second context is one in which induced abortion is either planned or in progress.
FETAL RESEARCH IN ANTICIPATION OF BIRTH. Many of the ethical issues involved in fetal research conducted at any stage of gestation in anticipation of birth closely parallel the ethical issues in research on newborns. The main reason for the close parallel is that the further development of the fetus or newborn into an adult person is planned. No research procedure that is likely to threaten the life or damage the health of a future person would be either proposed or carried out by responsible scientists. For this reason research not intended to benefit a particular fetus (in anticipation of birth) or a particular newborn is generally constrained by the no-risk or minimal-risk rule (U. S. Commission for the Protection of Human Subjects, Polkinghorne). That is, the research must be judged to pose either no risk at all (as in certain observational studies) or only minimal risk to the potential subject. For research intended to benefit a particular fetus or newborn, a careful weighing and balancing of likely benefits and harms to the subject is required (Polkinghorne; 45 C.F.R. 46.204).
The major difference between neonatal research and fetal research in anticipation of birth is that the fetus is contained within the pregnant woman's body, and any research intervention will require physical contact with, or at least physical proximity to, the pregnant woman. Thus fetal research inevitably and simultaneously affects a pregnant woman. For this reason it requires a careful weighing and balancing of the risks to her, as well as her informed consent.
Just as fetal research inevitably affects a pregnant woman, research on pregnant women inevitably affects the fetus. In the 1990s some commentators noted that a tendency to focus on fetal well-being resulted in the exclusion of women from clinical trials and in a paucity of information about the impact of medications and interventions on pregnant women or fetuses (Institute of Medicine). Their recommendations included presumed eligibility of pregnant women for participation in clinical studies, whether or not direct fetal benefit is anticipated. In the United States the revised Code of Federal Regulations accounts for the connectedness of the woman and fetus and modifies the minimal risk standard in that it allows for greater than minimal risk research in which the risk to the fetus is caused solely by interventions or procedures that hold out the prospect of direct benefit for the woman or the fetus (45 C.F.R. 46.204).
Many clinical procedures that are now routinely employed in obstetrical practice were first tested on pregnant women and fetuses in anticipation of birth. One early therapy was the use of exchange transfusions to overcome Rh incompatibility between a pregnant woman and her fetus. The worldwide epidemic of HIV infection and AIDS provided the context for important research affecting fetuses in the 1990s. In one groundbreaking randomized clinical trial, the antiviral drug azidothymidine (AZT) was administered to HIV-infected pregnant women in an effort prevent the transmission of infection to their fetuses, and was found to reduce the risk of vertical transmission by 66 percent (Sperling et al.).
One of the problems associated with early HIV research was that the impact of interventions to prevent maternal to child transmission was only measured with respect to fetal well-being; outcomes affecting pregnant women were not measured (Faden et al.). In the late 1990s the tendency to focus on fetal outcomes while ignoring those of women gained greater attention as one of several ethical issues surrounding experimental techniques now known as maternalfetal surgery.
While surgical therapies for prenatally diagnosed lethal conditions have been investigated since the early 1980s, this type of fetal research gained considerable attention in the late 1990s and early 2000s due to several ethical issues associated reports on the use of maternal-fetal surgery to correct fetal myelomeningocele (Lyerly et al.). Myelomeningocele is a condition involving incomplete closure of the spinal cord during fetal development and may be associated with bowel and bladder dysfunction, weakness or paralysis of the lower extremities, and cognitive difficulties. Investigators hypothesized that some of the neurologic damage associated with myelomeningocele occurred in utero due to exposure of the spinal cord to amniotic fluid, and thus that closure of the defect prior to birth would be associated with fewer adverse consequences in the neonate. Therefore, surgical closure of the spinal cord defect before birth, involving an operation on the pregnant woman and fetus, has been attempted and has raised many clinical and ethical issues.
One issue raised was whether it was appropriate to perform interventions associated with greater than minimal maternal and fetal risks in order to correct a non-lethal fetal anomaly. Previously the risks of maternal-fetal surgery had been justified in part because their aim was to correct otherwise lethal fetal anomalies, such as severe urinary tract obstruction, hydrocephalus, and congenital diaphragmatic hernia. Myelomeningocele, on the other hand, is an anomaly that is compatible with a normal life. A related concern was that willingness to perform this procedure reinforced discriminatory attitudes toward individuals with disabilities, like those with spina bifida (Myelomeningocele). Another concern raised was the failure to collect data on outcomes related to women, even though the techniques involved experimental surgery on both women and fetuses. Commentators emphasized that both the woman and fetus needed to be considered research subjects. Other concerns included the tendency to view these procedures as innovative therapy rather than research, and the adequacy of the informed consent process in pregnant women with a potentially sick fetus. As techniques to diagnose and potentially treat prenatally diagnosed conditions improve, the ethical issues surrounding maternal-fetal surgery for myelomeningocele will continue to be relevant to the conduct of fetal research in anticipation of birth.
FETAL RESEARCH IN ANTICIPATION OF OR DURING INDUCED ABORTION. Fetal research conducted before or during induced abortion could have various aims. One possible goal would be to develop better techniques for prenatal diagnosis, for example, by means of fetoscopy or chorionic villi sampling. Another possible goal would be to study whether drugs, viruses, vaccines, or radioisotopes cross the placental barrier between pregnant woman and fetus. A third aim of such studies could be to develop techniques for induced abortion that are safer for pregnant women or more humane in the termination of fetal life. Fourth, during abortion by hysterotomy (a seldom-used procedure similar to a cesarean section), fetal physiology can be studied after the fetus has been removed from the uterus of the pregnant woman and before the umbilical cord has been severed (Walters, 1975).
Commentators on the ethics of fetal research in anticipation of induced abortion have always been aware that a pregnant woman who intends to terminate her pregnancy can change her decision about abortion even after a research procedure has been performed. In addition in rare cases an attempt at induced abortion results in a live birth. Thus except in the case of research procedures performed during the abortion procedure itself, the distinction between a fetus-to-be-aborted and a fetus-to-be-born is statistical rather than metaphysical. One study performed for the U.S. Commission for the Protection of Human Subjects in the 1970s estimated the change-of-decision rate between a visit to an abortion facility and the scheduled time of termination to be in the range of 1–2 percent (Bracken).
The possibility that a pregnant woman may change her decision to undergo induced abortion after a research intervention sets an outer limit on the types of interventions that prudent researchers would be willing to perform. For example it would be useful to know at what stages of pregnancy alcohol, drugs, or viral infections are most likely to produce malformations in human fetuses; however, in the view of most commentators on the ethics of fetal research, such studies ought not to be performed in humans. In the words of the Peel Committee report, "In our view it is unethical for a medical practitioner to administer drugs or carry out any procedures on the mother with the deliberate intent of ascertaining the harm that these might do to the fetus, notwithstanding that arrangements may have been made to terminate the pregnancy and even if the mother is willing to give her consent to such an experiment" (United Kingdom, 1972, p. 6).
Even if research likely to cause serious damage to the fetus is ethically proscribed, there are at least two different ethical standards that can be adopted with respect to fetal research in anticipation of or during induced abortion. The first standard asks for equal treatment of the fetus-to-be-born and the fetus-to-be aborted. In brief this standard requires either that one should perform research procedures on fetuses-to-be-born concurrently with performing the same procedures on fetuses-to-be-aborted, or at least that one should be willing to perform the same procedure on both groups of fetuses. In practice this standard would be virtually equivalent to the no-risk or minimal-risk rule discussed in connection with fetal research in anticipation of birth (McCormick; Walters, 1975; Ramsey, 1975; Polkinghorne).
An alternative standard would reject the equal-treatment requirement. What is proposed instead is a kind of case-by-case approach to fetal research (U.S. Commission for the Protection of Human Subjects; Fletcher and Ryan). For example if the primary risk of a research procedure like chorionic villi sampling is that it will cause abortion in a small percentage of pregnant women, then it can be argued that research on this diagnostic procedure should be performed on women who plan to undergo induced abortion. If the research procedure itself is unlikely to injure the fetus, then the major remaining risk is that the abortion that the pregnant woman planned to have induced in the future would instead occur spontaneously. The major ethical questions remaining in a case of this kind have to do with the timing of abortion: Is a later rather than an earlier induced abortion less respectful of the developing fetus? Does a later abortion entail greater risks to the physical and mental health of the pregnant woman?
An important dimension of the fetal research discussion is the possibility that research procedures will cause pain to the fetus (Steinbock). One of the difficulties in coming to terms with this issue is that the word pain probably has different meanings at different developmental stages. The anatomical basis for simple spinal reflexes seems to be present in human embryos at about 7.5 weeks post fertilization. Between the ninth and twelfth weeks of development, the fetal brain stem begins to function as a rudimentary information processor. However only at twenty-two to twenty-three weeks of gestation is the cerebral neocortex connected to the other parts of the brain (Flower). Presumably the fetal capacity to perceive pain would differ at each of these three steps, but it is difficult to know precisely to what extent painful stimuli would be felt or remembered.
Research on Aborted, Live Embryos and Fetuses
There are major conceptual difficulties involved in describing a previously implanted entity that is expelled or removed alive from a pregnant woman's body (or removed alive from attachment to an artificial placenta). One candidate term is abortus; another is fetus ex utero or embryo or fetus outside the uterus. Adjectives applied to such entities include previable or nonviable and viable. A viable fetus outside the uterus is in fact a newborn infant, albeit one that may be seriously premature. In addition the notion of viability is elastic, sometimes seeming to mean the gestational age, weight, or length at which the smallest known infant has survived, at other times seeming to mean the stage at which a stipulated percentage of infants survive, given the assistance of technological means of life support.
Three circumstances can be envisioned in which the question of research on formerly implanted, living embryos or fetuses could arise. First, the surgical removal of an ectopic pregnancy could provide a still-living embryo or fetus. Second, a spontaneous miscarriage could result in the delivery of a live embryo or fetus. Third, an already implanted embryo or fetus could be aborted by means that make it either possible or likely that an intact, living embryo or fetus will result from the abortion procedure.
There is no clear consensus on the ethical justifiability of research on living human embryos or fetuses outside the uterus. In the United Kingdom, two official reports reflect a clear trend in a more conservative direction. In 1972 the Peel Committee affirmed the scientific value of research on clearly previable fetuses outside the uterus and permitted many kinds of research on such fetuses (United Kingdom, 1972). However the Polkinghorne Committee report of 1989 expressly rejected the position of the Peel Committee, arguing that the only morally relevant distinction was between living and dead fetuses, not the distinction between previable and viable fetuses (Polkinghorne). In the United States the U.S. Commission for the Protection of Human Subjects allowed no significant procedural changes in the abortion procedure solely for research purposes and restricted what could be done with the live, delivered embryo or fetus to intrusions that would not alter the duration of its life. Recommendation 1100 by the Parliamentary Assembly of the Council of Europe (1989) also discussed "the use of human embryos and fetuses in scientific research." Its recommendation clearly reflected the ambivalence of ethical opinion on research involving live embryos or fetuses out-side the uterus. After stating that "Experiments on living embryos or foetuses, whether viable or not, shall be prohibited," the recommendation continued as follows: "None the less, where a state authorises certain experiments on nonviable foetuses or embryos only, these experiments may be undertaken in accordance with the terms of this recommendation and subject to prior authorisation from the health or scientific authorities or, where applicable, the national multidisciplinary body" (Council of Europe, p. 6).
Since 1978 the ethical discussion of research involving implanted fetuses and live, aborted fetuses has matured, but it has proceeded largely along the lines established in the 1970s. In contrast the success of clinical IVF has given new impetus to the ethical debate about research on preimplantation embryos. In the future it is at least possible that new methods for sustained embryo and fetal culture in vitro will give rise to additional ethical challenges.
leroy walters (1995)
revised by anne drapkin lyerly
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