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Article Excerpt
Introduction
Since the first report of the derivation of human embryonic stem cells (hESCs) in 1998, (1) ethical debate has raged around hESC research. The primary, if not exclusive, concern raised in relation to hESC research is the inescapable reality that this research results in the destruction of human embryos. Stem cell research is not the only type of research performed using human embryos, and it is not the only focus of those who object to the use of human embryos in research. (2) But because stem cell research holds enormous promise in terms of its potential clinical applications, and because it is often linked in the public consciousness with somatic-cell nuclear transfer (roughly synonymous in the lay understanding with "cloning"), it has become a flash-point at the intersection of science, medicine and ethics.
Human embryos are inevitably destroyed in hESC research. Those who oppose embryo research because they ascribe full moral status to the embryo therefore take the view that such research is ethically impermissible. Those who hold that human embryos do not share the same moral status as persons, but do have heightened moral status compared to other human tissues or biologic matter, are prepared to permit stem cell research, but insist that as few embryos as possible be destroyed in the process. (3) Many who hold this view also oppose the creation of human embryos solely for research purposes, meaning that such research is acceptable only insofar as it uses embryos that are supernumerary to the reproductive needs of those for whom they were created. (4)
But even among those who do not agree that embryos deserve special treatment, morally speaking, ethical unease has been expressed around the use of human embryos in stem cell research. Concerns around the commodification of gametes and embryos, and the related worry that women's reproductive capacity and reproductive material will be exploited have been articulated. (5) Questions have also been raised about who decides what research is worth pursuing and about the use of public funds to support research into what are likely to become very expensive therapies, possibly available only to the "privileged few." (6)
In spite of these concerns, many nations, including Canada, have decided to pursue a research agenda that includes hESC research. In light of the fact that such research is permissible, we must consider the process by which those who will donate embryos to the pursuit of hESC research will provide consent.
In this paper, I consider the unique ethical issues that arise in hESC research. I then discuss consent policy in relation to human subjects research generally, and look to existing Canadian policy regarding consent to hESC research (the Guidelines for Human Pluripotent Stem Cell Research (7) and the Assisted Human Reproduction Act), (8) with a view to critiquing consent policy. I also reflect on the subject of consent to the donation of fresh embryos to research, given the national attention this matter has received. Finally, I conclude by suggesting points for discussion at the workshop for which this background paper has been written.
1. Stem Cell Research and Human Subjects Research
Regulation of research involving human subjects is of relatively recent vintage, having originated as an outcome of the Nuremberg trials that followed the Second World War. (9) The aim of regulation of research using human subjects is to attempt to find the elusive balance between permitting the conduct of scientifically sound, potentially beneficial research and ensuring that human subjects are treated in an ethically appropriate manner during their participation in research. Two important mechanisms employed to safeguard the interests of research subjects are the requirement of consent to research and mandated research ethics board (REB) review. In this paper, the focus will be on the former.
Research using human tissue is considered "human subjects research." (10) As such, research on gametes and embryos--specific human tissues--clearly constitutes human subjects research. Although hESC research falls within the broad category of human subjects research and shares much in common in terms of ethical issues raised by such research, (11) specific ethics policy and legal rules have begun to evolve in response to the burgeoning field of stem cell research. These rules are in many ways similar to rules governing research using human tissues, but they also have some unique aspects. Are the differences between hESC research and other human subjects research sufficient to warrant unique legal and policy responses? In particular, should consent rules be substantively different for hESC research? A number of arguments have been made that seem to favour the "unique rules" approach. Canadian research ethics policy, for example, treats gametes and embryos as distinct from other types of human cells and tissues, noting that "the topic of human reproduction invokes a discussion of fundamental values," and that such research "engenders acute ethical concerns for both the research community and the public at large." (12) Most prominent among the reasons given for treating embryo research as unique relates to the moral status of the embryo. While I have no interest in replaying the moral status debate here, it is important to consider what is unique about embryonic stem cell research, with a view to raising some concrete questions about whether consent rules in this research context should be different from the rules in other research involving human tissue and, if so, how they should be different.
As noted in the introduction, a significant ethical issue (and arguably the main impetus for the debate) in the context of human embryonic stem cell research is the preliminary question of whether such research is acceptable at all--what Hank Greely calls the "what's in the dish" question. (13) This question has played (and continues to play) an important role in the development of many national policies on embryo research, including that of Canada. (14) Moral objections to the use of embryos in research have existed ever since the very possibility of such research has been on the scientific horizon, (15) and such objections show no sign of abating as embryonic stem cell research continues to move forward. In essence, the "moral status" question can be boiled down as follows: is the embryo a human being from the moment of fertilization, or is it "too rudimentary in ... development to yet have interests and be the subject of moral duties"? (16) If the former, then research that will result in embryonic destruction is impermissible; if the latter, such research is permissible, at least in some circumstances.
In spite of the unsettled nature of the moral status question, Canada (like many other nations) (17) has decided that, in some circumstances at least, it is ethically appropriate to conduct research on human embryos. The compromise position adopted in the Assisted Human Reproduction Act (AHR Act) and the Canadian Institutes of Health Research (CIHR) Guidelines prohibits the creation of embryos for research purposes, but permits the use of embryos that are no longer required for reproductive purposes.
This policy stance is the background against which we must assess legal and ethical issues related to consent, and to an extent, at least, further debate about the moral status of the embryo is irrelevant. This is an important point insofar as the primary motivation behind creating ethical and legal rules unique to stem cell research has been this argument about the special moral status of embryos. In a sense, adopting a position that embryonic stem cell research is permitted but is nevertheless distinct from other research using human tissue may be viewed as a compromise between adopting the "embryo as human being" argument and the position that an embryo is nothing special, no more than a collection of cells. In other words, although the embryo is not the same thing as a person and can therefore be used in research, it deserves special respect and should not be discarded or destroyed cavalierly. While embryo research is a subset of the broader category of "human tissue research," it is a special subset that requires unique and specific rules. Arguably, however, the resulting policy stance is unprincipled and logically inconsistent. (18) To a degree, it appears that the compromises that have been made are founded on a desire to appease both the scientists who want to push ahead with stem cell research and those who ardently oppose the conduct of such research on the basis of the moral status of the embryo.
In addition to the moral status of the embryo, concerns have been raised about commodifying human cells and tissues, commodifying women's reproductive capacity and exploiting women. (19) Of course, concerns also exist relating to the commodification of human cells and tissues in the health research context, as do concerns about the potential exploitation of research subjects (the source of the cells and tissues). (20) Just as worries have been raised that selling gametes or embryos is tantamount to selling babies, similar arguments have been made in the human tissue research context, that selling cells or tissues amounts to selling persons.
Aside from the question of the moral status of the embryo, a major distinction between stem cell research and other research involving the use of human cells or tissue is the role that women play in research using human gametes and embryos. Human tissue generally can be donated for research purposes by both sexes and such donation is equally invasive, regardless of the sex of the donor. While both an egg and a sperm cell are required in order to create an embryo, obtaining ova from women is quite a different matter than obtaining sperm cells from men. Sperm donation is relatively uninvasive and involves no drug therapy or medical procedures.
Ovum donation, by contrast, is extremely invasive. It involves several steps, each requiring medical intervention. In some circumstances, women will be prescribed medication to interrupt their normal menstrual cycle. They then undergo ovarian stimulation, which entails the use of medication to stimulate the ovaries to produce more than the usual one egg per menstrual cycle. Additional medications are required to prevent premature ovulation. During the period of ovarian stimulation, frequent blood tests and ultrasound examinations will take place in order to determine the woman's response to fertility drugs and to track the progress of maturing ovarian follicles. Ova are then retrieved using ultrasound-guided aspiration, a minor surgical procedure that involves the use of anaesthesia. There are risks involved in all of the medical interventions that take place in the context of an egg donation cycle, including side effects related to the medications used to interrupt the donor's menstrual cycle and the drugs used in ovarian stimulation. (21) In addition, there is a risk of ovarian hyperstimulation syndrome (OHSS), which can cause severe complications in about 0.05-5% of IVF cycles (22) and in very rare cases, can be fatal. Finally, there are potential long-term risks of ovarian stimulation, which are currently unknown. (23) Some studies suggest a link between ovarian stimulation and the risk of developing ovarian and other cancers later in life, (24) but more research is needed in order to substantiate or rule out this concern.
As a result of the risks involved in procuring ova, stem cell research is unique in the human subjects research context. It may also be unique from the perspective of infertility patients / potential research subjects. Studies show that in general, individuals and couples with supernumerary cryopreserved embryos do not choose to donate these embryos to research. (25) Further, as Klock has noted, even those who initially consent to donate embryos to stem cell research frequently change their minds after some time away and emotional distance from the clinical experience. (26) Researchers have begun to explore the reasons for the ambivalence potential embryo donors feel about the disposition of supernumerary embryos, (27) and have found that donors conceptualize their cryopreserved embryos in a multitude of ways ranging from "biologic material," to "virtual children" or siblings of their living children. (28)
Not only are there unique considerations around what is being donated to research in the stem cell context, there are distinctive issues related to who is donating human reproductive material for use in stem cell research. Hank Greely has identified a number of different groups of potential tissue donors for human embryonic stem cell research. These are: couples donating supernumerary cryopreserved or fresh embryos that were created for reproductive purposes; women donating fresh ova for reproductive purposes; women donating fresh ova for research purposes; men or women donating somatic cells for use as nuclear donor cells; and men donating sperm. (29) As Greely has pointed out, distinct consent issues may be raised by some of these groups. (30) In particular, concerns arise around consent in the "fresh" embryo context, given the time pressure involved, and around the donation of ova solely for research purposes. As David Magnus and Mildred Cho have noted, women donating ova solely for purposes of research are undergoing the significant risks entailed by egg donation with no corresponding benefit to themselves. (31) As such, Magnus and Cho suggest that these donors are more like living organ donors, whose donations are not always accepted. Indeed, in the case of organ donation there is at least a significant and real benefit to be gained by the recipient, whereas in the case of stem cell research, it is uncertain whether any clinical benefit will result. (32)
Clearly, there are other ethical issues to consider in relation to hESC research, including those related to resource allocation and the possibility that the availability of treatments using stem cell lines may pose a threat to public health care systems. (33) But these are questions about the much larger debate as to the legitimacy of pursuing a research agenda that involves stem cell research, and as such do not raise issues specifically related to consent to participation in hESC research. It appears, based on the foregoing, that there may indeed be reasons to depart from traditional consent rules in the hESC research context. The next section of the paper considers to what extent this has been done in Canadian law and policy and explores whether and, if so, how we should deviate from existing consent principles.
2. Consent
a. Consent and Human Subjects Research
The key reason for the importance of consent to participation in research in law and ethics is to demonstrate respect for the dignity and autonomy of research participants. To be sure, the concept of human dignity is slippery...
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