What is the Unborn? The Scientific Case

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  • October 31, 2018

What is the Unborn? The Scientific Case

How can two human parents create offspring that isn’t human, but later becomes so?

To review, the pro-life argument is formally stated as follows:

Premise #1: It is wrong to intentionally kill innocent human beings.

Premise #2: Abortion intentionally kills innocent human beings.


Conclusion: Abortion is morally wrong.

The science of embryology establishes that from the earliest stages of development, the unborn are distinct, living, and whole human beings. True, they have yet to grow and mature, but they are whole human beings nonetheless. Leading embryology textbooks affirm this.

For example, in The Developing Human: Clinically Oriented Embryology, Keith L. Moore & T.V.N. Persaud write: “A zygote is the beginning of a new human being. Human development begins at fertilization, the process during which a male gamete or sperm…unites with a female gamete or oocyte…to form a single cell called a zygote. This highly specialized, totipotent cell marks the beginning of each of us as a unique individual.” T.W. Sadler’s Langman’s Embryology states: “The development of a human begins with fertilization, a process by which the spermatozoon from the male and the oocyte from the female unite to give rise to a new organism, the zygote.” Embryologists Ronan O’Rahilly and Fabiola Müller write, “Although life is a continuous process, fertilization is a critical landmark because, under ordinary circumstances, a new, genetically distinct human organism is thereby formed.”6

We’ve known these truths since the mid 19th century:


  • In its 1859 Report on Criminal Abortion, the American Medical Association (AMA) understood that “the independent and actual existence of the child before birth as a living being” was a scientific truth.


  • A century later, embryologist Bradley M. Patten wrote, “It is the penetration of the ovum by a spermatozoan and resultant mingling of the nuclear material that each brings to the union that constitutes the culmination of the process of fertilization and marks the initiation of the life of a new individual.”7


  • Prior to advocating abortion, former Planned Parenthood President Dr. Alan Guttmacher was perplexed that anyone would question these basic scientific facts. “This all seems so simple and evident that it is difficult to picture a time when it wasn’t part of the common knowledge,” he wrote in his book Life in the Making.8


  • In 1981, Dr. Watson A. Bowes of the University of Colorado Medical School told a U.S. Senate Subcommittee that “the beginning of a single human life is from a biological point of view a simple and straightforward matter – the beginning is conception.”9


  • The report from that same Senate Subcommittee concludes, “Physicians, biologists, and other scientists agree that conception marks the beginning of the life of a human being—a being that is alive and is a member of the human species. There is overwhelming agreement on this point in countless medical, biological, and scientific writings.”10

Objections and Replies

Objection #1— “There is no consensus on the humanity of the unborn. We have no facts, only judgment calls.”

During our debate at U.C. Berkeley, Dr. Malcom Potts replied to my pro-life argument with an appeal to skepticism. He asserted that no one has the truth on the humanity of the embryo, that people disagree. “There are no absolutes in embryology, only judgment calls.”

Including that one? If nobody has the truth, why listen to Dr. Potts?

His reply is deeply problematic for many reasons.

First, if it’s true we don’t know if the embryo is human, that’s an excellent reason not to kill the embryo since we may be taking a human life. As former President Ronald Reagan once observed, if you are out hunting and you see bushes rustling in front of you and you’re not sure if that’s the deer you’ve been after or your best friend, are you going to open fire?

Second, how does it follow that because people disagree, nobody is right? People once disagreed on whether the earth was flat or round, but that didn’t mean there were no right answers. They once disagreed on slavery, but that didn’t mean there wasn’t a right way to think. As Hadley Arkes points out, the absence of consensus does not mean an absence of truth.11 Moreover, if disagreement means that nobody is right, then Potts’ own position is falsified. After all, pro-lifers disagree with it. So do many embryologists—like those cited above.12 And if there are no facts about the embryo’s humanity, only judgment calls, one can’t help but ask if that statement about embryology is a fact or just a judgment call? Even worse, if the truth about embryology is merely subjective, why study it in the first place? Indeed, if everything is a judgment call, there is nothing in principle that would prevent two embryologists from holding completely contradictory positions on the subject, yet both positions being equally valid. Absurd!13

Third, on this particular question—is the embryo a distinct, living, and whole human being? —we do indeed have a consensus: Embryology textbooks, like those I cited earlier, uniformly state that each of us began as an embryo. First, the embryo is alive, having all the characteristics of a living thing. Second, it’s distinct from both parents, having its own genetic fingerprint. Third, it functions as a whole living organism rather than a mere assemblage of cells. Since these facts are obvious to everyone paying attention, it explains why embryologists describe (not define) the beginning of life as happening at conception. Peter Singer, an ethicist at Princeton University, defends abortion and infanticide. Yet he recognizes that skepticism on the humanity of the unborn is unwarranted:

“It is possible to give ‘human being’ a precise meaning. We can use it as the equivalent to ‘member of the species homo sapiens.’ Whether a being is a member of a given species is something that can be determined scientifically, by an examination of the nature of the chromosomes in the cells of living organisms. In this sense, there is no doubt that from the first moments of its existence an embryo conceived from human sperm and eggs is a human being.”14

Philosopher David Boonin, author of A Defense of Abortion (Cambridge, 2002), argues that we are identical to the embryos and fetuses we once were. He writes, “A human fetus, after all, is simply a human being at a very early stage in his or her development.”15

Critics of the pro-life position may reply that biological life is continuous (an “unbroken tree” as some put it), thus, we can’t say when the embryo’s life begins. This is demonstrably false. Just because life is continuous between generations does not mean we can’t tell when an individual human begins to exist. As my colleague Jay Watts points out, we certainly don’t seem to struggle distinguishing the mother from her aborted offspring. When was the last time you heard an abortionist say that due to the complexity of when life begins and the indistinguishable nature of the whole life process, he accidentally killed the mother instead of the fetus?

Of course, it’s possible pro-life advocates are wrong. Maybe the science of embryology doesn’t say what they think it does regarding the humanity of the unborn. However, an appeal to relativism just won’t do. Critics must show why the pro-life advocate is mistaken.

It won’t be easy. Since we are, as a matter of objective fact, separate human beings from our parents, that distinction must take place at some point in time. At some time in the past, there was only sperm and only egg. Then some time after that there was something completely new—both genetically new and ontologically new. What events are candidates for that decisive moment? Only one—the one embryologists routinely cite: fertilization.

Objection #2— “Any Ol’ Cell Will Do.”

Ronald Bailey of Reason magazine insists that we gain no real knowledge from the science of embryology. Bailey argues that embryonic human beings are biologically human only in the sense that every cell in the body carries the full genetic code, meaning that each of our somatic (bodily) cells has as much potential for development as any human embryo. Put simply, Bailey would have us believe that there is no difference in kind between a human embryo and each of our individual cells.16

This is bad biology. Bailey is making the rather elementary mistake of confusing parts with wholes. The difference in kind between each of our cells and a human embryo is clear: An individual cell’s functions are subordinated to the survival of the larger organism of which it is merely a part. The human embryo, however, is already a whole human entity. Robert George and Patrick Lee say it well. It makes no sense to say that you were once a sperm or somatic cell. However, the facts of science make clear that you were once a human embryo. “Somatic cells are not, and embryonic human beings are, distinct, self-integrating organisms capable of directing their own maturation as members of the human species.”17

Dr. Maureen Condic points out that embryos are living human beings “precisely because they possess the single defining feature of human life that is lost in the moment of death – the ability to function as a coordinated organism rather than merely as a group of living cells.” Condic, Assistant Professor of Neurobiology and Anatomy at the University of Utah, explains the important distinction between individual parts and whole human embryos overlooked by Bailey:

“The critical difference between a collection of cells and a living organism is the ability of an organism to act in a coordinated manner for the continued health and maintenance of the body as a whole. It is precisely this ability that breaks down at the moment of death, however death might occur. Dead bodies may have plenty of live cells, but their cells no longer function together in a coordinated manner.”18

From conception forward, human embryos clearly function as whole organisms. “Embryos are not merely collections of human cells,” writes Condic, “but living creatures with all the properties that define any organism as distinct from a group of cells; embryos are capable of growing, maturing, maintaining a physiologic balance between various organ systems, adapting to changing circumstances, and repairing injury. Mere groups of human cells do nothing like this under any circumstances.”19

In short, embryos are not clumps of cells. Nor are they fertilized eggs. Sperm and egg die in the act of fertilization. That is, each surrenders its constituents into the make up of a new living organism, the human embryo. Sperm and egg, like somatic cells, are parts of larger human beings while the embryo is a whole (albeit immature) member of the human family.

Objection #3Twinning

Because an early embryo can split into two, some defenders of abortion claim it’s not an individual human before day 18 post-conception. Now this is s a very odd claim given it does nothing to establish abortion as a fundamental right throughout pregnancy. At best, it justifies abortion only until day 18, which rules out nearly all abortions.

Nevertheless, the claim that twinning refutes the pro-life position is not persuasive. First, how does it follow that because an entity may split that it wasn’t a whole living entity prior to the split? As Patrick Lee points out, if you cut a flatworm in half, you get two flatworms! Does it follow there was no flatworm prior to the split?20 Second, if an early embryo does not have a right to life because a twin can be formed from it, and a twin can be formed from any of us through cloning, then none of us has a right to life.21 Third, if the early embryo prior to twinning is merely a hunk of cells and not a unitary organism, why doesn’t each cell develop individually into a new living entity? Instead, just the opposite is true. Robert George writes, “These allegedly independent, non-communicating cells regularly function together to develop into a single, more mature member of the human species.” This fact shows that the cells are interacting from the very beginning, “restraining them from individually developing as whole organisms.”22

Objection #4Miscarriages

Abortion-choice advocates sometimes point to the high number of miscarriages as proof the early embryo is not a unitary being. But this does not justify abortion or call into question the humanity of the unborn. How does it follow that because nature spontaneously aborts high numbers of embryos that a) they are not living human beings or b) I may intentionally kill them? Many third-world countries have high infant mortality rates. Are we to conclude that those infants who die sooner rather than later were never whole human beings? Admittedly, these miscarriages are tragic. But as journalist Andrew Sullivan points out, earthquakes kill thousands in 3rd world countries, but that does not justify mass murder.23

Objection #5Hydatidiform moles

At a recent debate, my opponent disputed my case that human life begins at conception. “Not so fast,” he argued. “Not all acts of fertilization result in a human organism. Hydatidiform moles can form from an early embryo. Therefore, you cannot say that conception results in a human life. You may get a molar pregnancy.” Here my opponent confuses necessary and sufficient conditions. I’m not claiming that everything that results from a sperm-egg union is human, only that every human conceived through natural reproduction begins that way. Regarding hydatidiform moles in particular, they do not result from normal, biologically complete conceptions; rather, they arise from flawed or deficient fertilizations. As Dr. Maureen Condic points out, “despite an initial (superficial) similarity to embryos, hydatidiform moles do not start out as embryos and later transform into tumors.” Rather, “they are intrinsically tumors from their initiation.” Thus, “they have no intrinsically directed capacity to develop into a human being.”24

To help understand Condic’s point, consider “The Alphabet Song” and “Twinkle Twinkle Little Star.” Both sound alike in the first five measures, but they are different songs from the beginning. One does not morph into the other.25

Objection #6Soul Confusion

Dr. Malcom Potts claims that “an embryologist cannot say when life begins any more than an astronomer can say what happens to the soul after death.” Well, Dr. Potts has many colleagues in the field of embryology who say he is flat wrong on the empirical question of when life begins. True, science can’t tell us if humans have souls—that’s a philosophical question. But the science of embryology can tell us when individual humans come to be, and the evidence there is clear and to the point: From the earliest stages, you were a distinct, living, and whole human being. Moreover, we don’t need to decide if embryos have souls to determine if they are worthy of protection. For example, the law doesn’t take position on whether 35-year-olds have souls, but it still forbids intentionally killing them.26 Likewise, we don’t need to posit a soul to say that embryos are distinct, living, and whole human beings.

Objection #7Religion can’t tell us when life begins and thus can’t say abortion is wrong.

Dr. Potts says no one can say when life begins, that it’s a judgment call religious in nature. His argument is a non-starter. First, the question of when human life begins is an empirical question, not a philosophical or religious one. To get our answer, we don’t consult the Bible or the teachings of any religious sect. We consult the science of embryology. True, science can’t tell us how to treat any living thing—we use philosophy to determine that—but it can tell us what the unborn are, that is, whether or not they are living human beings. Second, Dr Potts makes a category error. As mentioned earlier, arguments are either true or false, valid or invalid. The fact that a given argument has religious underpinnings does not de facto mean that it’s bad. The Declaration of Independence (US 1776), Lincoln’s Second Inaugural Address, and Martin Luther King’s “Letter from Birmingham Jail” all have their metaphysical roots in the concept of man bearing the image of God. Are these documents cut off from rational inquiry simply because they are rooted in religion? As Robert P George and Christopher Tollefsen point out, “Human embryo ethics is, in this regard, no different from the ethics of our treatment of minorities or dependents. Human beings are capable of understanding, through reason, that it is morally wrong and unjust to discriminate against someone because he is of a different race or has a different ethnic heritage. And we are capable of understanding that it is wrong and unjust to discriminate against someone because of his age, size, stage of development, location, or condition of dependency. Human beings are perfectly capable of understanding that it is morally wrong and unjust to treat embryonic human beings as less than fully human. We need religion to support such claims in this domain no more than we need religion to support claims of racial justice or the rights of the disabled.”27

Objection #8The burning fertility clinic

Comedian Patrick S. Tomlinson thinks he’s got a slam-dunk defense of abortion. Actually, it’s not his; it’s a rehash of a thought experiment first put forward by Michael Sandel, Dean Stretton, George Annas, and Ellen Goodman—to name a few. Nevertheless, Tomlinson thinks he’s destroyed the pro-life case for the humanity of the unborn and the inhumanity of abortion. In a series of tweets, he writes:

Whenever abortion comes up, I have a question I’ve been asking for ten years now of the “Life begins at Conception” crowd. In ten years, no one has EVER answered it honestly. It’s a simple scenario with two outcomes. No one ever wants to pick one, because the correct answer destroys their argument…Here it is. You’re in a [burning] fertility clinic. Why isn’t important. The fire alarm goes off. You run for the exit. As you run down this hallway, you hear a child screaming from behind a door. You throw open the door and find a five-year-old child crying for help. They’re [sic] in one corner of the room. In the other corner, you spot a frozen container labeled “1000 Viable Human Embryos.” The smoke is rising. You start to choke. You know you can grab one or the other, but not both before you succumb to smoke inhalation and die, saving no one. Do you A) save the child, or B) save the thousand embryos? There is no “C.” “C” means you all die. In a decade of arguing with anti-abortion people about the definition of human life, I have never gotten a single straight A or B answer to this question. And I never will. They will never answer honestly, because we all instinctively understand the right answer is “A.” A human child is worth more than a thousand embryos. Or ten thousand. Or a million. Because they are not the same, not morally, not ethically, not biologically. This question absolutely eviscerates their arguments, and their refusal to answer confirms that they know it to be true. No one, anywhere, actually believes an embryo is equivalent to a child.

Right away, Tomlinson is off the rails. The abortion controversy is about who we may intentionally kill. His thought experiment is about who we should intentionally save.

See the problem?

Put simply, how does it follow that because you save one human over others, the ones left behind are not fully human and we may kill them? Suppose I’m in a burning lecture hall with those reading this essay. I can either save all of you, my gentle readers, or my 17-year-old daughter Emily Rose. Who gets left behind? You’re toast. I’m saving her first. Does it follow that you are not human or that I may shoot you on the way out?

Let’s review the pro-life syllogism:

P1: It is wrong to intentionally kill an innocent human being.

P2: Abortion intentionally kills an innocent human being.


C: Abortion is morally wrong.

Suppose pro-lifers save the five-year-old instead of the embryos. How does Tomlinson’s analogy refute the pro-life syllogism? It doesn’t. At best, it shows pro-lifers inconsistently apply their ethic, not that they are mistaken about the science of embryology or the immorality of intentionally killing an innocent human being. Consider the reverse: Instead of saving the five-year-old, you save 10 of your own frozen embryos. Do your actions call into question the humanity of the child left behind?

Now, I don’t think pro-lifers are inconsistent, for reasons I discuss below. But let’s play along. Suppose pro-lifers say the unborn are human but, when called to act on their stated beliefs, shrink from doing so. What follows?

Nothing that changes the essential nature of the unborn. An abolitionist in the 1860s might save the family dog over a transient slave, thus exposing the abolitionist’s real beliefs about slaves. How would that in any way change the essential nature of the slave or, worse still, justify killing him? Let’s go further: Suppose no whites in 1860 believe slaves are human. How does their belief about the slave determine what he is?

In short, our intuitions are not infallible. Richard Topolski and his colleagues at George Regents University surveyed 500 people with a hypothetical scenario in which a bus is hurtling out of control, bearing down on a dog and a human. “Which do you save?” The startling answer was, “that depends.” Respondents asked, “What kind of human and what kind of dog?” Nearly everyone would save a sibling, grandparent or close friend rather than a strange dog. But when people considered their own dog versus strangers, votes for the dog skyrocketed. An astonishing 40 percent of respondents, including 46 percent of women, voted to save their dog over a foreign tourist.28 Are we to conclude the stranger is less human than a pet dog?

Imagine a medical complex is on fire. I can save 100 frozen embryos or 1,000 terminally-ill cancer patients lying unconscious in their final hours of life. If I save the embryos, are the cancer patients less human and less valuable than embryos? Not at all. Rather, additional considerations guide my actions. While embryos and cancer patients are equally valuable, the embryos stand a better chance of getting out alive. A few will make it to birth. Thus, given the triage situation confronting me, I save the embryos.

Similar considerations guide me to save the five-year-old over the frozen embryos. Once again, both are equal in fundamental dignity. However, the five-year-old has a much greater chance at survival. Frozen embryos face challenging odds going from canister to womb to birth. Even when successfully thawed, many embryos spontaneously abort after implantation. Moreover, a five-year-old can feel pain while embryos cannot. Given a choice between letting a human being die in profound agony and letting others die with no agony at all, you save the former. Finally, there are social concerns. The five-year-old is known by family, extended family, and the local community. If he perishes, dozens—if not hundreds—are impacted by the loss. Not so with embryos, where painful grief is largely restricted to immediate family.

Of course, none of these considerations diminish the humanity of the embryo or justify intentionally killing him. Rather, they are tiebreakers when deciding to save one human being over others. A Secret Service agent will take a bullet for the president of the United States but not an ordinary citizen. And if Washington DC is attacked, he will save the president over an entire city. What does that say about the intrinsic value of those left behind?

Nothing. While all human life is sacred, the consequences of losing the president are catastrophic. The Secret Service knows this and acts accordingly. In sum, Tomlinson’s thought experiment misses the point entirely. Ramesh Ponnuru writes, “The moral question posed by the burning-building scenarios is the extent to which you can show favoritism without being unjust.” In these scenarios, he writes, “we might reasonably take account of all kinds of things—family ties, the life prospects of potential rescuees, the suffering they would undergo if not rescued, etc—that aren’t relevant to the question: Can we kill them?”29


Objection #9Women don’t grieve miscarriages.

Maybe they do and maybe they don’t. How does this prove the unborn are not human or that intentionally killing them is okay? Put simply, my feelings about something don’t change what it is. I would grieve the death of my own child far worse than the thousands of kids who die daily in developing countries, but it doesn’t follow my own child is more human than those kids. It just means I’m emotionally attached to my own offspring.

Objection #10The embryo doesn’t look human.

Perhaps so. But this is completely beside the point. Mannequins may look human but aren’t remotely so while the Elephant Man did not look human but was. The question is not what an entity looks like, but what it is.

Admittedly, our intuitions may not immediately identify an early embryo as one of us. After all, it doesn’t look like a cute newborn, but it does look exactly as a developing human should look at that stage of development. Philosopher Richard Stith suggests a thought experiment for rethinking our intuitions about the early embryo. Imagine you are on a Mexican safari in pre-digital days and you’ve got a Polaroid Camera. The early Polaroid was an awkward looking device with a major advantage: Instead of waiting weeks for photo processing, it spit out your picture on the spot, allowing you to watch it develop before your eyes in about 90 seconds. While on the safari, at just the right moment, you capture a Polaroid picture of a black jaguar leaping across the trail in front of you. Black jags are almost never photographed, but you got it! National Geographic will pay you big bucks for that pic! While you are breathlessly waiting for the image to emerge, I rip the Polaroid camera from your hands and tear up the emerging picture. You would be furious! Suppose I replied, “There’s no jaguar in that picture. It’s just a brown smudge on a white piece of paper!” Will that satisfy you? Never! You’d rightly point out, “The jaguar in the picture was already there. We just couldn’t see him because he was still developing.” Likewise, from the one cell stage, you were already there. We just couldn’t see you because you were still developing. That’s the science of embryology!30

To review, the following objections do not refute the pro-life advocate’s case from science:


  1. People disagree on when life begins—The absence of consensus does not mean an absence of truth.
  2. Sperm and egg are alive—Yes, but this confuses parts with wholes. Sperm and egg are parts of larger human beings. Embryos are whole human beings who, like all living organisms, function in a coordinated manner.
  3. Twinning—Just because an embryo splits doesn’t mean it wasn’t fully human (flatworm example).
  4. Miscarriages—Just because nature spontaneously triggers a miscarriage does not mean the unborn are not human or that intentionally killing them is okay.
  5. Molar pregnancies—They don’t start as human embryos and morph into tumors. They never were human embryos.
  6. Soul confusion—Whether living things have souls is a philosophical question. When human beings come to be is an empirical one. We can answer the latter without answering the former.
  7. Saying life begins at conception is a religious argument—Arguments are true or false, valid or invalid. Calling an argument “religious” is a dismissal, not a refutation.
  8. Burning fertility clinics—How does it follow that because I save one human over others, the ones left behind are not fully human?
  9. Women don’t grieve miscarriages—Many do. However, my feelings about something do not change what it is.
  10. The embryo doesn’t look human—But it does look exactly like a human should at that stage. The question is not what an entity looks like, but what it is.