"Fetal 'personhood': getting the facts straight"

Dianne N. Irving
Assistant Professor, History of Philosophy/Bioethics
De Sales School of Theology
Washington, D.C.
Christian Life Commission of the Southern Baptist
"Life at Risk: Crises in Medical Ethics"
Nashville, Tennessee
Copyright March 3, 1993
Edited for clarity and format, July 21, 2004
Reproduced with Permission


We find ourselves engulfed in one ethical dilemma after another these days - many brought on by the explosion of medical technology. At times it seems that the "theory" has not had time to catch up with the pace of these rapid changes. We especially, as Christians, find it difficult - and sometimes even down-right embarrassing - to seek for clarification, or even frame our responses - from our Christian faith's perspective. We must respond. Yet how relevant can our responses possibly be these days, if grounded in our "religious" Christian traditions. Doubts abound!

Such, frankly, were my anxious thoughts as well, as I prepared to address the literature on fetal personhood. Fairly convinced initially that "personhood" probably started about 14 days (based on my rough survey of the arguments) I settled into sorting out the mile-high stack of articles. Some argued for "immediate personhood", i.e., at fertilization there is present a human being who is necessarily and simultaneously a human person. Some, on the other hand, argued for "delayed personhood", i.e., at some later point during human embryogenesis an embryo or fetus finally becomes either a human being - or a human person. These latter embryological events are referred to as the "biological marker events of fetal personhood".

However, I realized fairly quickly that not only was the philosophy used in these debates "a little weird" - but more disturbing to me - as a former research chemist and biologist - the science used was text-book incorrect - in virtually all of the arguments (other than those arguing for "personhood" at fertilization). In short, I was required to spend a good deal of extra time tracking down each and every scientific point, and correcting it through research and myriads of conversations and meetings with other scientists at NIH and elsewhere. It was important to me to straighten the science out, as these scientific observations would be the starting point of my philosophical deliberations.

On the other hand, I am one of those who believes that true and accurate science, philosophy and the Scriptures would complement rather than contradict each other. And as Scripture relates: "He is known by the things that are". 1 So in my own way, as both a scientist and a realistic philosopher, I have taken this as a sort of private covenant. I resolved that once I straightened out the science, I would just see where it would lead me - and it led me to a quite different - and, frankly, politically incorrect - position!

The question of when "personhood" begins is central to all of the issues in ethics and bioethics. In the context of philosophy, how one defines a human being or a human person determines what ethical choices one should make. The issue concerns not only that of abortion, but so many other bioethical issues which are interrelated with it - especially those at the beginning and the end of life - e.g., embryo and fetal research, gene screening and therapy, and in vitro fertilization; - or the definition of brain death, the withdrawal of food and water for a patient in "PVS" (a misnomer), and euthanasia. Virtually each person sitting in this room today will be dramatically and personally touched by how we - as Christians or as society at large - define a human being. Public policy is already based on someone's definition of a human being! The question to ask is: is their definition correct or defensible?

My talk will necessarily become a little technical - and I apologize for that. But I ask your indulgence today to at least consider seriously the information I am about to discuss, for these days the contemporary social and political debates on the bioethical issues are won or lost on just these fine, seemingly esoteric scientific or philosophical points. Neither the rest of the academic community, nor we as Christians can afford to remain aloof from these issues anymore. The good news is that the position of those Christians who believe in the inalienable dignity and personhood of the pre-born child - at all of his or her growing stages - is indeed based on quite solid scientific and philosophical grounds!

Too often we hear the claim of the relativist: "We just don't or can't know what a human being or a human person really is", or, "There just is no consensus or agreement on what the definition of a human being or a human person is, so why should one person's or one group's definition be preferred over any other. The definition of a human being or of a human person cannot be objectively determined, and so must remain a relative one."

This claim, I will argue, is not only objectively refutable and ridiculous; the very claim of relativism is self-refuting. If the theory of relativism claims that all theories are relative, then the theory of relativism is also relative, and hardly worth the trouble. I also want to emphasize that we can and do have an objective and empirically-based definition of a human being or human person, and that - other than conceptually, or mentally - one cannot really split a human being from a human person. "Personhood" begins when the human being begins. If ever there was an example of a time when solid reasoning and scientific facts can inform the faith we already have, this is surely one.

First, I will just summarize some of the most important arguments against "immediate personhood". For example, many claim that the early human zygote, embryo or fetus is either not really a human being, but rather sort of like tissues or organs of the mother. Many are arguing that even if it is a human being, it is not yet a human person (and therefore deserving of the same moral and legal protections as all other human persons). Both of these kinds of arguments are blatantly incorrect and, as I will demonstrate, grounded in text-book wrong scientific facts, as well as in pass philosophical "facts" and theories which, in philosophical jargon, sport a massive mind/body split. This mind/body split renders them theoretically and practically indefensible, as there can then be no interaction of any sort possible or explainable between the mind and the body.

In order to draw you into the issue as quickly as possible, I want to pose a few questions to clarify exactly what is at stake when we define a human being or a human person in one way or another. To paraphrase an old philosopher: "A small error in the beginning leads to a multitude of errors in the end." In other words, if our definition of a human being or a human person is incorrect - even in part - then the consequences of this incorrect definition are profound. So I pose the question - how would you yourself define a human person? Is a rock, a tomato, or a frog a human being? ...those who are old and senile in a nursing home? How about Alzheimer's, Parkinson's patients, stroke, comatose, or "PVS" patients? ... drunks and alcoholics; drug addicts; the homeless, poor; prisoners; the emotionally ill and depressed; mothers-in-law; teen-agers; the physically handicapped; the mentally infirm; children under 7 years of age; a new-born baby; the fetus before the mother has given birth (or, at 6 months, 8 weeks, 35 days, 14 days, 6 days, 2 days, fertilization, or the egg or the sperm). These latter examples actually constitute some of the different biological markers at which various writers claim that there is present a human person. Obviously there is some disagreement about exactly when we have, definitionally, a human person present. And that period of time between fertilization and about 8 weeks is the grayest area, i.e., the seemingly most difficult and most controversial stage. It is particularly this period of time on which I will focus most of this discussion.

My approach to refute "delayed personhood" will be the following. First, I will lay out in very general terms the kinds of arguments offered for the so-called "biological marker events of personhood". Second, because the science and philosophy are so intertwined, I must address briefly the correct science that we do know, and that philosophical "ball-park" which does - incredibly - realistically match that correct biology, and grounds the argument for "immediate personhood". Third, I will point out in more detail some of the major specific arguments for "delayed personhood", and indicate their use of incorrect science and philosophy.


First let me brush in broad strokes the kinds of arguments for "personhood" - or when, during embryological development we have a human being or a human person. There are three general categories of arguments. First, "personhood" begins when the human being begins - at fertilization. There is no distinction between a human being and a human person - they cannot be split. At some definite point in time during the process of fertilization, substantial change has taken place, and a new, unique, living, individual human being who is a human person is present. Embryological development, on the other hand, is not substantial change, but only accidental change, or continuous development in size, shape and specialization. I will go into more detail in a moment.

The second kind of argument is concerned with the actual physiological "capacity" required to be present if there is to be a human person. "Capacity" is meant here in a rather passive sense; that is, the focus is on whatever nature is required as a precondition for there being a human person present. This argument (like the third one) breaks down into two types of "capacities". One is the capacity to exercise so-called "rational attributes" (e.g., loving, hating, willing, reasoning, interacting with the environment around one, consciousness or self-consciousness, etc.). This is a rather "rationalistic" philosophical criteria. The other is the capacity to be sentient, or to feel pain or pleasure. This is rather an "empiricist" or materialistic criteria. Both criteria are based on the requirement that there is a split - somehow - between a human being and a human person.

The third kind of argument is concerned with the actual exercising of these capacities. Thus some will argue that there is no person present until those "rational attributes" are actually actively operating. Others will argue there is no person present until full brain integration and full sentience is actually actively operating. What I want to stress up front is that any of the arguments from both the second and third group are biologically impossible and refutable, and that any of the arguments from the third group lead necessarily to the moral acceptance of the infanticide of perfectly normal healthy infants and children - whether one realizes this at first or not.

Thus we have this general overview of three kinds of arguments to identify: (1) those in which there is no split or distinction between a human being and a human person; (2) those which do make such a split or distinction - based on a physiological capacity or nature as a precondition for either "rationality", or "sentience", and; (3) those which also make such a split or distinction - but based on the actual active exercising of either the capacity for rationality, or for sentience. If there are any old philosophy "buffs" here in the audience, perhaps you might be beginning to see yet another "pattern" forming! (And this is why the science and the philosophy are so integrally intertwined). Interestingly enough these three general categories of arguments actually tend to very roughly parallel a stretch of the history of philosophy: an Aristotelean; a Cartesian; a rationalist or an empiricist school of thought. This leads me to my second section, i.e., the connection between the science and the philosophy.


First, although a question about "natures" seems to be fundamentally a philosophical one, any philosophical reflections, analyses or accounts about the nature of a human being or person must begin or start with the empirically observable biological facts. 2 Otherwise our philosophical concepts actually bear little or no relation or resemblance to the real world which we are trying to understand and explain by those concepts. Instead we are left with multiple half-truths or fantasies - or wishful thinking! Only in this way can we have a realistic or objectively-based definition of a human being - one that is not relativistic.

Operationally, what is the connection between a thing's nature and the biological facts? Put briefly, the answer is that we can know what a thing is, i.e., its nature, by observing its actions or functions - how it behaves, what it does. We know that a thing acts according to the kind of thing it is, i.e., its nature. That is simply an empirically observable fact. In first-year chemistry, microbiology or genetics, students are given "unknowns" which they must identify by means of the kinds of actions or reactions exhibited by these "unknowns". Thus Na burns orange, and cobalt burns blue/green - or beta-hemolytic streptococcus can only be grown on specific culture medium containing blood, but not on other mediums. And a particular member of a plant or animal species is identified microscopically by the number of chromosome present in a single cell. Indeed, this is the obvious principle behind any basic or experimental research. The research biologist first observes the actions, reactions, functions of a biological entity and reasons from these specific kinds of actions back to the specific kind of nature it possesses. It is this nature which directs and causes such characteristic actions. As biology texts themselves discuss it: function follows form.3

Further, a thing is not only characterized by its nature which determines the specific kinds of actions it can do - but that same nature limits the kinds of actions it can do. That is, there are certain actions which a thing can not do because it does not have the specific kind of nature it would need to do it. For example, birds have wings and so can fly - but stones, dogs or human beings can't fly; corn stalks produce ears of corn and corn proteins and corn enzymes - but acorns, tomato plants or asteroids do not and cannot produce corn or corn proteins. Frog embryos direct the formation of frog tissues and organs - but they cannot direct the formation of human tissues and organs.


Apply these considerations to the point at hand. To determine what a human being or person is is really not all so difficult as is often claimed. There are voluminous biological facts which we do know already about the human body and its embryological development. Clearly by observing and studying these known biological facts - how the human being begins his or her biological existence as a specifically human zygote, and the kinds of specifically human functions and human actions that take place during embryological development - we can then determine to a very sophisticated extent the nature of a human being or a human embryo - or what it is. So I will turn now to a brief consideration of the biological facts about which most if not all of us are already aware.

Before fertilization there exist a human sperm (containing 23 chromosomes) and a human ovum or egg (also containing 23 chromosomes -the same number, but different kinds of chromosomes). 4 Neither the sperm nor the egg, singly, by itself, can become a human being - even if implanted in the womb of the mother. They are only gametes - they are not human embryos or human beings. In contrast, the single-cell human zygote formed after fertilization contains 46 chromosomes (the number of chromosomes which is specific for members of the human species) - and these 46 chromosomes are mixed differently from the 46 chromosomes as found in the mother or in the father - that is, they are unique for that human individual. This is why an embryo or fetus is not just a tissue or organ of the mother! Thus with fertilization substantial change has taken place, i.e., a change in natures. And if allowed to "do his or her own thing", so to speak, this human zygote (who is already a he or a she!) will biologically develop continuously without any biological gaps throughout the embryonic, fetal, neo-natal, childhood and adulthood stages - until the death of the organism. And with the advent of in vitro fertilization techniques, we can see that the early human embryo can develop in vitro on his or her own without the nutrition or protection of the mother for quite a while - someday, perhaps, even until "birth"!

I want to reiterate that a human gamete is not a human being or a human person. The number of chromosomes is only 23; it only acts or functions biologically as an egg or as a sperm, e.g., it only makes egg or sperm enzymes and proteins, etc., not specifically human enzymes and proteins; and by itself it does not have the actual capacity or potency yet to develop into a human embryo, fetus, child, or adult. And in that sense gametes are only possible human beings (i.e., non-existent human beings). Only after the sperm and the egg chromosomes combine properly and completely do we have a human being.

After fertilization there is not substantial change, but only accidental change. 5 That is, the nature of the human being does not change, only its accidents change. Thus embryological development does not entail substantial change, but only accidental change. Once it is a human being it stays a human being, and acts and functions biologically as a human being from the start. The human zygote produces specifically human enzymes and proteins; he or she forms specifically human tissues and organ systems, and develops humanly continuously from the stage of a human single-cell zygote to the stage of a human adult.6

This is observed empirically. A human zygote does not produce cabbage or carrot enzymes or proteins, and does not develop into a rock, an ear of corn, nor into a cat, a horse, a chicken, or a giraffe. Empirically it is observed that a human zygote produces specifically and characteristically human proteins and enzymes at the moment of fertilization - as demonstrated recently, for example, by experiments using transgenic mice7 - and that he or she develops continuously throughout embryological development in a specifically and characteristically human way.

In short - the biological facts demonstrate that at fertilization we have a truly human nature. It is not that he or she will become a human being - he or she already is a human being. We know that empirically. And this nature or capacity to act in a certain characteristic way is called, philosophically, a nature or a potency.8 A human zygote or embryo is not a possible human being;9 nor is he or she a potential human being;10 he or she is a human being.

Now, this is irrefutable empirical evidence that at fertilization there is a human being; but is there also a human person - or not? It is in this shifting from the paradigm of a human being to that of a human person where the philosophy comes into play again. Is a human being also a human person; or are they different things? Which philosophy is adequate to cope with this biological data?

With even only a cursory rummaging through the history of philosophy, there is one major "realistic" philosophical "ball-park" which would deny any essential distinction between a human being and a human person - they cannot be split or separated from each other - except perhaps only conceptually. This philosophy was part of a 2500 year old tradition which was the bath water, so to speak, that was thrown out with the baby! It is the philosophical ball-park, for example, of Aristotle-the-biologist.11 For Aristotle - as well as for others - his major metaphysical and anthropological treatises argue consistently for a human substance with no mind/body split (although there is evidence of a serious Platonic streak in his De Anima -that a-typical and historically problematic treatise of Aristotle's - followed unblushingly by some, and so often quoted by contemporary scholars - as well as historians who researched for Roe v. Wade). In an Aristotelean "ball-park", matter cannot exist apart from the form - at least not in this world. The human being is defined as one composite substance - the vegetative, sensitive and rational powers of the "soul" together with the human "body".12 The whole soul, he wrote, is homogenous, and in each part of the body as one whole composite:

In each of the bodily parts there are present all the parts of the soul, and the souls so present are homogenous with one another and with the whole; this means that the several parts of the soul are indisseverable from one another.13 (emphasis added)

And this means that the "soul" is not a separately existing substance in itself, nor is it found in any one particular organ, e.g., the heart or the brain. And Aristotle addresses the very possibility of a "being-on-the-way", or an "intermediate human being", railing against the anthropological consequences of Plato's or Pythagoras' mind/body split when he very sarcastically retorts: "Yet how are we to believe in such things?"14 Although Aristotle-proper did not actually use the term "person", he clearly would have to concur that a human being is always a human person, for neither form nor matter can exist on their own as two different things or independent substances. Rather, matter and form (or the soul and the body) are two different aspects of one thing.

Another philosopher puts an even finer gloss on Aristotle's anthropology. To paraphrase him: "The name of "person" (and he uses that term) does not belong to the rational part of the soul alone, nor to the whole soul alone - but to the entire human substance (or, subsistens)."15 This means that the whole soul, whole body and its act of existing constitutes one personal substance entire - with no separate and troublesome independent "parts" which are claimed to be true and independent substances themselves.

In this philosophical "ball-park", then, a human being is a human person; and the later characteristics which we will look at in these debates, such as "rational attributes", autonomous willing or sentience, are really only consequential and secondary or accidental actions which follow upon certain powers (not "souls") which themselves follow upon the essential nature of the human being itself.16 That nature is defined as the single, whole, formal, material and existential human substance. The nature of a human being, then, is not defined in terms of only one aspect of the soul (e.g., the "rational" aspect), or in terms of any one activity of the soul, but in terms of the whole complex human being. As it is put:

...the soul must be in the whole body [and therefore not just in the brain], and in each part thereof ...for to the nature of the species belongs what the definition signifies; and in natural things, the definition does not signify the form only, but the form and the matter...so it belongs to the notion of man to be composed of soul, flesh and bones.17 (emphasis added)

What significance does this have for the arguments for "delayed personhood"? It is claimed that the "rational" soul - which "organizes and directs embryological development" - is not infused until sometime up to about the third month.18 But then what explains the specifically human organization of the human embryo and human fetus up to that point? Hasn't the work of this supposed "delayed rational soul" already been done - as empirically verified? If so, then this biological evidence of specifically human organization which we do empirically observe must be accounted for by the presence of the human soul right from the beginning. We also empirically observe specifically human functions and activities from the beginning - e.g., the production of specifically human proteins, enzymes, etc. If so, then this biological evidence of specifically human functions and activities which we do empirically observe must be accounted for by the presence of the human soul right from the beginning.

Again, this "human rational soul" must include virtually the vegetative and sensitive powers,19 for there is no such thing, at least in this earthly life, as a part of a "rational soul" alone, or even a whole soul alone as a complete human being. The whole human complex (body and soul) must be present together at once. At least I have never seen a human being on this planet who did not have a body! And apart from the biological and conceptual absurdity of an "intermediate human being", if there were only a "human vegetative" soul present at first, how do we explain the production of specifically human enzymes and proteins - instead of carrot or corn enzymes - from the very start? If there were only a "human vegetative and sensitive" soul present, how do we explain the production of specifically human tissue and organs - instead of only giraffe or gorilla organs and systems? If the human soul cannot be split (and must contain all three powers at once), and if specifically human enzymes, proteins, tissues, organs and structures are empirically observed - which they are - then the human rational soul must be present at the very beginning along with the human vegetative and sensitive "powers" of the human soul. And these powers must exist as a composite with the human body which it is organizing and whose functions and activities it is directing. Thus, at fertilization the "matter" is already appropriately organized as human; we empirically observe it as human and as developing humanly.20

So far the scientific facts and the philosophical concepts match. At this point I want to take a closer look at the biological facts after fertilization, i.e., those of human embryological development. Along the way I will point out several other different biological "marker events" of personhood which have been argued by others. All of these writers will make a distinction between a human being and a human person - supposedly based on these biological marker events. The use of certain biological data which they will use to support their arguments will also be addressed.


As noted above, the newly formed single-cell human zygote consists of 46 chromosomes and non-nuclear DNA in which are coded the specific directions for virtually all of the processes of embryological development. The content of this initial pool of genetic information never changes throughout embryological development. But - to give an example of the second kind of argument (which stresses the presence of a genetically human capacity or nature) - it has been argued21 22 that not all of the "information" needed is present in this single original cell, that some of the information comes from "positional molecules" in later stages of development, and some even comes from molecules originating from the mother. They conclude that the original human zygote does not contain all of the information needed to be a self-directing, human individual, and therefore it is neither a human being nor a human person.

This biological data is incorrect. First, "molecular information" or "positional information" is simply not the same as genetic information - what the fertilization argument is talking about. Also, molecular or positional information is itself coded in the original single-cell human zygote. As the well-known embryologist Moore discusses at great length, the genetic information in the original human zygote itself determines what molecules will be formed, which in turn determine what proteins and enzymes will be formed, which in turn determine which tissues and organs will be formed. In genetics this is called the "cascading effect".23 That is, the information in the original single-cell human zygote "cascades" throughout embryological development -each previous direction causing the specific formation of each succeeding direction. Thus, all "positional" or "molecular" information or direction is already determined itself by the information which preceded it, and ultimately by the original information in the single-cell human zygote.24 Second, although the information in the human zygote may direct the absorption of molecules from the mother -that hardly means that the maternal molecules or the mother herself determines the very nature of the growing embryo or fetus which she is nurturing.25 The nature of the embryo or fetus, we know, is determinable and set by the formal biological genetic make-up of the zygote from which he or she continuously develops - and the directing of this absorption or use of maternal molecules is done by the genetic information within the embryo or fetus -not by the mother. Those are simply the correct biological facts. As Jerome Lejeune, the internationally renowned human geneticist has testified:

...each of us has a unique beginning, the moment of conception... As soon as the twenty-three chromosomes carried by the sperm encounter the twenty-three chromosomes carried by the ovum, the whole information necessary and sufficient to spell out all the characteristics of the new being is gathered... 26 (emphasis added)

Next, it is argued by some that this original single cell divides neatly first into 2 cells, then into 4 cells, then into 8 cells, etc.27 This biological data too is incorrect, and has consequences in understanding the argument about "totipotency". As known and published in embryological textbooks for over 60 years28the original single cell divides into 2 cells - and then only one of those cells divides, giving 3 cells. After a time the other cell divides, making it 4 cells, and then 8 cells, etc.

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