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The US Supreme Court’s Dobbs decision striking down the constitutional right to abortion (which has sparked a renewed debate over when human life begins) all but guarantees that the issue of setting research limits on fetal tissue testing will be contested in the US courts and in the court of public opinion.
Many of those with ethical doubts look at the issue through an idiosyncratic lens. The discord in their analytical approaches is troubling — and provides an unreliable basis to address the issue. Those focusing on the moral issues raised by the Supreme Court — and question at what point is the embryo a person — are likely to claim that the 14-day rule should be abolished altogether, and no embryo research should be permitted.
According to one interpretation, by professor Sonia Suter of George Washington University, Dobbs vests in the state the right to make laws affecting
the ‘potential life’ and for the ‘unborn human being’ [which] can be expressed through laws showing ‘respect for and preservation of life at all stages of development (emphasis added). It makes no distinction between implanted embryos and embryos created in vitro (i.e., in the laboratory, lit. ‘in the glass’, whether petri dish or test tube), whether fresh or frozen.
Extending this reasoning to the debate over the 14-day rule is inevitable. Numerous American and Canadian ethicists have expressed concerns about setting a hard 28-day limit as there is little scientific, and in some cases limited ethical reasoning behind this number. As prominent ethicist Henry (Hank) Greely, Director of the Stanford Center for Law and the Biosciences, has written, “Even though I do not personally give strong moral status to embryos, the idea of doing research on 18-day-old [sic] human embryos is disturbing.”
While Warnock, Jasanoff, Greely and other ethicists believe the public needs to sound in, they provide no basis upon which an untutored populace should base their decisions. The crux of the question, then, is who should decide? Should this be a scientific question to be determined (or at least guided) by science bodies? Or a purely moral and ethical issue to be determined by society-at-large?
Why 14 days? Can the past offer guidance to the future?
In 2017, Baroness Warnock explained why the committee she oversaw in 1984 set the 14-day limit.
“We did pick on a number of days after which we understood that the embryo began to develop more swiftly toward becoming a curled-up fetus with a spinal cord and a central nervous system,” she wrote.
The groundbreaking report resolved a dichotomy in her committee; she recommended what she claimed was a middle ground between science and ethics in an attempt to reconcile proponents and opponents of embryo research — even though she didn’t give much credence to a science-based inquiry as an objective tool. As she wrote in her 204 book The Making of British Bioethics:
First, scientific evidence offered no resolution, as both sides used data on embryological development to justify their particular standpoint. The interpretation of scientific ‘facts’ here was not a neutral activity, since the question of which facts mattered was clearly shaped by an individual’s moral preferences.
She highlighted the relevant biological factors including the initial development of the nervous system and the beginning of gastrulation:
In biological terms, the 15th day of embryo development is the point when the primitive streak forms: that is, the beginning of gastrulation when three layers of germ cells differentiate. The 14th day is therefore notable, because the embryo is then individuated and can no longer become a twin.
But Warnock and her group gave the biological basis for the 14-day solution a moral gloss: the cut-off was decided upon to mark the ability of the cellular entity to supposedly feel pain, inferred from the beginnings of the nervous system development, but was couched as “sentience”, even though this would be a far cry from sentience as is generally conceived. And the biological demarcation of a definite, single human individual — or individualization — was considered the beginnings of the emergence of the individual’s identity, a psychological or social concept.
Deeper dive into biology: What’s an embryo?
Perhaps, philosopher-Warnock gave the science short shrift. Let’s explore further.
Strictly speaking a zygote (the product of the fertilization of the gametes, egg and sperm,) isn’t even called an embryo, at least in the scientific universe, until two or three weeks after the gametes unite. Immediately after fertilization, the cells begin dividing. After four days, at the 16 to 30 cell stage of development, the undifferentiated clump of cells looks like a mulberry — and is called a ‘morula’ (Latin for mulberry).
On the fifth day of development, the morula now has a structure, becoming the blastocyst (the point IVF researchers and embryologists test the motley cellular group for genetic defects to assure the best chance of successful impregnation). The blastocyst structure has an inner cell mass, the embryonic stem cells, from which the embryo develops.
Two weeks or so after fertilization the first nervous system cells are formed, the entity is implanted in the uterus, and the entity is now called an embryo and begins developing further. This is point where “the primitive streak” appears and at which time gastrulation begins — meaning the pre-embryo entity transforms from a one-dimensional layer of epithelial cells (blastula) and reorganizes into a multilayered and multidimensional structure called the gastrula. Twinning can no longer occur.
Technically, the first two weeks of pregnancy is referred to as the germinal or pre-embryonic stage, although colloquially many use the term “embryo” to refer to all the pre-fetal stages. During the following eight-week period, the embryo develops the head, spine and internal organs. At that point, the entity is called a fetus — slowly emerging as the blueprint for a single individualized person to be born at the end of a successful pregnancy.
It appears, then, that the 14-day rule does have a biological basis which transcends the two features cited by Warnock: the “moral grounds of sentience and individuality”; and the technical infeasibility of cultivating embryos in-lab that has existed until recently. Clear biological staging and developmental criteria are triggered at this stage in development.
Still, the prime question remains unresolved: While technology has now made extending the time to experiment possible, just because we can, doesn’t automatically mean we should. A major problem is that the community of stakeholders are using terms differently. The legal (and popular) definition of an “embryo” differs depending on who you ask, which might contribute to the confusion and surely impacts the solution. In a definition only a lawyer (or philosopher) could love, countries with strict ‘embryo laws’ define an embryo as a cell or cluster of cells with the potential to grow into a human being, thereby obfuscating and ignoring long-accepted biological benchmarks.
Technology to the rescue?
How do we resolve these competing complex concepts? The 14-week rule could be extended on a case-by-case basis, although that wouldn’t address the moral or religious concerns (e.g., when is a developing embryo a person?) nor the biological ones. If there is a biological, bright-line divide, it is unlikely to occur at arbitrary points of time, such as 14 or 28 days.
Recent advancements may offer a way out of this conundrum. Non-egg sperm constructs, called organoids, have been developed from stem cells and are being used for research on prenatal development. Stem cells are undifferentiated cells with the potential to develop into a line of tissues or even organs. As opposed to embryos which have the potential to develop into a complete human, the potential for stem cell development is far more limited, and so can be seen as ‘morally safer.’
Other means of developing test models involve synthetic human entities with embryo-like features (called SHEEFs or synthetic human entities with embryo-like features) and some forms of organoids (i.e., miniature 3D tissue models of organs). These models have developed synthetic embryos with the capacity to develop further although so far, they’ve only been developed in mice.
Experiments on these synthetic embryos (contrived without egg or sperm) appear to bypass the objections raised in extending the 14-day rule, although they may generate ethical dilemmas of their own (a discussion for another day). So, experimenting on SHEEFS could provide similar knowledge gleaned from experimenting on one-month-old embryos, making research up to the 28-day-old limit unnecessary, and thereby obviating the dilemma.
Yet some scientists and ethicists are using the possibility of experimenting on these SHEEFS, let’s call this point A, as a basis to advocate extension of the 14-day rule, point B. I’m not sure how they get from point A to point B. I can only surmise that these advocates don’t understand the legalities or moralities involved in experimenting on a human embryo.
Barbara Pfeffer Billauer, JD MA (Occ. Health) Ph.D. is Professor of Law and Bioethics in the International Program in Bioethics of the University of Porto and Research Professor of Scientific Statecraft at the Institute of World Politics in Washington DC.
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