Pro-choice advocates will insist that the human embryo doesn’t become a human being until birth or at least sometime late in pregnancy. Pro-life people generally agree with the scientific consensus that human life begins at fertilization; once the ovum cell is fertilized by the sperm cell, a new, genetically distinct human organism comes into existence. But I sometimes come across pro-life advocates who believe human life begins at implantation or around that time, not at fertilization.
As an example, Don Marquis, famous for his essay “Why Abortion is Immoral”, believes the view that human life begins at fertilization to have serious problems (“Abortion and the Beginning and End of Human Life”, Journal of Law, Medicine, & Ethics 34 (1): 16-25 (2006)). His view of personal identity is animalism (aka the biological view of personal identity), which Eric T. Olson argues convincingly for in his books and articles. But Olson, despite believing we are essentially animals and are identical to the embryo as long as we are biologically continuous with it (in other words, as
long as the embryo develops into me in a continuous fashion), does not believe we are identical to the embryo at the single-cell zygote stage for this reason: he believes human beings become individuals after the potential for twinning is lost. Olson writes:
According to the Biological View, I started out as an embryo. Does that mean that I came into existence at the moment of conception? Not necessarily. The Biological View implies that I came into being whenever this human organism did. But it is unlikely that this human organism came into being at conception — that is, that it started out as a fertilized egg. When a fertilized egg cleaves into two, then four, then eight cells, it does not appear to become a multicellular organism — any more than an amoeba comes to be a multicellular organism when it divides. The resulting cells adhere only loosely, and their growth and other activities are not, at first anyway, coordinated in a way that would make them parts of a multicellular organism. The embryological facts suggest that a human organism comes into being around sixteen days after fertilization. (Eric T. Olson, “Was I Ever a Fetus?”, Philosophy and Phenomenological Research, 57 (1), 95-110, 1997)
Pro-choice philosopher Peter Singer and embryologist Karen Dawson, in an attempt to argue embryonic stem cell research should be pursued, argue an embryo created in a lab is not a human being because it lacks the potential to grow into an older human being on its own. An embryo in a petri dish can survive for about five days and then it will die if not implanted into a uterus. They write,
But can the familiar claims about the potential of the embryo in the uterus be applied to the embryo in culture in the laboratory? Or does the new technology lead to an embryo with a different potential from that of embryos made in the old way? Asking this question leads us to probe the meaning of the term ‘potential’…While the notion of potential may be relatively clear in the context of a naturally occurring process such as the development of an embryo inside a female body, this notion becomes far more problematic when it is extended to a laboratory situation, in which everything depends on our knowledge and skills, and on what we decide to do. This line of argument will lead us to the conclusion that there is no coherent notion of potential which allows the argument from potential to be applied to embryos in laboratories in the way in which those who invoke the argument are seeking to apply it. (Peter Singer and Karen Dawson, “IVF Technology and the Argument from Potential”in Embryo Experimentation: Ethical, Legal, and Social Issues, ed. Peter Singer, et al (Cambridge: Cambridge University Press, 1990), pp. 76-77, as quoted in J.P. Moreland and Scott B. Rae, Body and Soul: Human Nature and the Crisis in Ethics, (InterVarsity Press, Downers Grove, IL, 2000) p. 270)
Still other people, even some pro-life advocates I’ve talked with, believe that we shouldn’t consider an embryo at fertilization a human being because it can grow into things which aren’t humans, such as an empty sack or a tumor.
All three of these arguments are seriously flawed and reflect a faulty understanding of how human development works. I’ll briefly reply to each argument in turn below.
Olson believes that the embryo at its earliest stages is not an organism, but rather the organism exists as a unified whole at around sixteen days after fertilization. Now despite the fact that all embryology textbooks place the start of the organism at fertilization and not at any point after that, occasionally you’ll still have people arguing that it’s not an organized individual until after that point. Olson is simply wrong when he says that the embryological facts suggest that a human organism comes into being around sixteen days after fertilization because the entire field of embryology would disagree with him.
He compares the early embryo to an amoeba; as an amoeba does not become a multicellular organism when it divides, neither does the early embryo. But here, Olson is making the same kind of elementary mistake that a pro-choice advocate makes when they assert that sperm and ovum cells are alive but we don’t grant them a right to life, so the embryo doesn’t have a right to life. Olson is confusing the parts of the embryo (the cells) with the whole embryo, itself. An amoeba, by definition, is a unicellular being. So when it divides it only divides into other unicellular beings. And of course, some early embryos have the potential to split when they become twins, and two individuals will exist instead of just one as was the case before the split. So twinning is more comparable to the amoeba splitting. The cells of the embryo dividing are not comparable to the amoeba splitting because these are the cells of the embryo which are dividing while the embryo remains the same kind of thing it has been since day one — a human embryo, whose cells divide because it is in the nature of human beings to grow and develop.
Olson’s other point is that the cells of the embryo are not coordinated in a way that would make them parts of a multicellular organism but only loosely adhere to each other. This is a fairly common claim you hear but it’s simply wrong. Olson is misrepresenting the facts of embryology here. Developmental biologist Michael Buratovich addresses this argument. He writes,
The embryo…prepares for future events. For example, at the two-cell stage, the blastomeres synthesize a cell adhesion protein called E-cadherin. E-cadherin acts like cellular superglue, and the two-cell stage embryo makes it in anticipation of compaction, which occurs two days later. (Michael Buratovich, The Stem Cell Epistles: Letters to My Students About Bioethics, Embryos, Stem Cells, and Fertility Treatments, (Cascade Books, Eugene, OR, 2013), p. 58.)
He also shows, referencing philosophers Robert P. George and Christopher Tollefsen, that this idea of Olson’s ignores the goal-directed behaviors of the embryo. There are at least three goals of the embryo: get to the uterus and implant, form the structures necessary for successful implantation, and preserve its structure against the many hazards it might encounter. (Buratovich, ibid.) So the early embryo is still a coordinated whole organism, even at the very early stages of development. Olson is mistaken about the facts of embryology.
Singer and Dawson
Singer and Dawson (hereafter SD) argue that because the embryo conceived in a laboratory is completely dependent upon what we do to it, on our knowledge and skills, this means that the potential of an embryo created in a lab is wholly different from an embryo conceived naturally. But this dubious conclusion they draw from the unique circumstances of the conception of an embryo created in a lab relies on a faulty understanding of potential.
It should be quite obvious that SD’s argument is simply a more sophisticated version of the viability argument. The argument is essentially because an embryo is not viable in a petri dish in a lab, creating an embryo in a lab means that it does not have the same kinds of potential as one who is conceived naturally and relies on the natural processes of the mother’s body. But this shows no such thing. As happens quite often, embryos created in a lab can be implanted into a woman’s uterus and then will continue to develop normally, as if they had been conceived naturally in the woman’s Fallopian tube. This shows clearly that the embryo created in the lab has the same kinds of potentialities that an embryo conceived naturally does. It just will not continue to develop because it is not in an environment in which it can survive. An astronaut on a spacewalk or a deep sea diver swimming in the depths of the ocean are both completely dependent on our knowledge and skills to survive, on the technology they use to survive in those harsh environments. But this certainly wouldn’t justify a view that because they are now in environments in which they can’t ordinarily survive they suddenly have lost the potentialities that other human beings their age possess. In fact, it would be absurd to make that argument. Embryos created in a lab have the same potentialities because they are the same kind of entities — human beings.
The final argument I will address is the argument that human life doesn’t begin at fertilization because the embryo can simply grow into an empty sac, or some other kind of entity like a hydatidiform mole. But this argument doesn’t work, either. Whatever is human is human from the very beginning. It’s not the case that a human embryo will develop into an empty sac or a mole. If the entity in the womb is an empty sac or a mole, then it was always an empty sac or a mole. We just weren’t able to detect what it was yet. Even so, an embryo is an embryo from the very beginning, even if we can’t know for sure that it’s an embryo until later on, when the pregnancy can be detected.
Maureen Condic explains it like this,
…it is important to appreciate that simply because two living entities share some common elements or overlap in a sequence of biochemical events, they are not necessarily the same kind of entity.
Distinct biological entities that share some initial molecular events are similar to two musical works that begin with the same notes…For example, “Twinkle, Twinkle Little Star” and “The alphabet song” are identical until the fourth measure, yet they are distinct (albeit, very similar) songs. While listening to a CD recording, it would be impossible to determine which work is being performed until the first distinguishing note is heard, yet once this point is past, all prior notes provide clear evidence that a particular song was indeed recorded on the CD and was being played out from the first note. The CD does not begin playing random notes that resolve into a specific song, nor does it begin with one song and later “transform” into the other, nor does it begin playing “both” or “neither” song until the first distinguishing note is produced. From the beginning, it plays the single, specific song that is recorded on the CD. Indeed, prior to the CD being played, a sufficiently detailed examination of the recording (for example, analyzing the data encoded on the disc using a scanning probe atomic force microscope) would determine the precise song it contains without any ambiguity. (Maureen L. Condic, “A Biological Definition of the Human Embryo” in Persons, Moral Worth, and Embryos: A Critical Analysis of Pro-Choice Arguments, ed. Stephen Napier, (Springer Publishing, Philadelphia, PA, 2011), p. 216, emphases in original)
It’s just simply not the case that the embryo will develop into something non-human later on. A human embryo exists from the beginning, even if we don’t have the ability to tell what it is from that point.
These are not the only arguments I’ve seen for why life doesn’t begin at fertilization, at least in some cases, but instead at implantation (or sometime near). But these are, I think, three of the most persuasive arguments for the position. As I have shown here, each of the arguments rely on fundamental misunderstandings of some element of human development, whether it’s the biological aspects or the philosophical aspects. Once those misunderstandings are resolved, it remains clear that human life does indeed begin at fertilization.