I have written before on h0w we know the unborn are persons from fertilization. But now I'd like to address how we know the unborn are biological members of our species from fertilization. This is a basic, undeniable fact of science and yet I still encounter many people who deny this reality.
Before you can even answer the question of whether or not abortion is moral, you must first decide what the unborn is. For as Greg Koukl of Stand to Reason observes, if the unborn is not human, then no justification for elective abortion is necessary. It would be no different from having a mole removed or a tooth pulled. But if the unborn is human, then no justification for elective abortion is adequate.
If it’s true that no one can tell when human life begins, then the benefit of the doubt should go to life. We should not be aborting the unborn because there’s a chance we could be aborting living human entities. If a hunter hears a rustling in the woods, does he shoot right away or does he make sure the rustling wasn’t caused by another human? Unless he’s Dick Cheney, he’s going to make sure it’s a deer he’s aiming at and not a human (I owe my friend Josh Brahm for that joke). Or if you’re driving down a road in the dark and you see the outline of something that may be a child or may simply be the shadow of a tree, do you drive into it or do you slow down? Or if you’re about to blow up a condemned building and you’re not sure if someone’s inside, do you blow it up anyway or send someone in to make sure?
However, it’s not true that no one can tell when human life begins.
The unborn from fertilization are alive because they exhibit the properties of living things. They grow through cellular reproduction and division, they metabolize food for energy, and they respond to stimuli. In fact, the only thing the unborn need to survive are adequate nutrition, a proper environment, and an absence of fatal threats. That’s all any of us need. There is no point in human development at which the developing entity goes from non-life to living.
The unborn are also human from fertilization. We know that everything reproduces after its own kind; dogs have dogs, cats have cats, and humans have humans. They have separate human DNA from, and often a different blood type than, the mother. A white human embryo can be created in a petri dish, implanted into a black mother, and be born white. In fact, if the unborn organism were simply a “part of the mother’s body,” then following the law of transitive property (if A is a part of B, and B is a part of C, then A is a part of C), every pregnant woman would have four arms, four legs, two heads, four eyes, two noses, and roughly half the time male genitalia. But this is absurd. At no time during human development does the unborn ever go from non-human to human.
Finally, the unborn from fertilization are organisms. They are living human entities separate from the mother, with their own functional parts that work together for the good of the whole, developing themselves from within into a more mature version of itself, along the path of human development. Zygote, embryo, and fetus are not non-human entities, they are early stages of development in human life.
Philosopher Richard Stith once made a valuable observation. He discovered that the reason pro-choice people tend to think pro-life people are absurd is that they tend to think of the unborn entity as being constructed in utero, like a car on an assembly line. When does a car become a car? Is when when the frame resembles a car, or when the tires are attached, or when it drives off the lot? It requires an outside builder to put all the pieces together into what we understand is a car. A car is not present from the beginning, because the parts that make a car can be used in the construction of something else (such as a boat or a plane).
However, the unborn’s development is different. He or she directs his or her own development from within. He or she does not have an outside builder, he or she directs his or her own internal growth and maturation, and this entails continuity of being. Professor Richard Stith illustrates the difference with the following analogy:
“Suppose we are back in the pre-digital photo days, and you have a Polaroid camera and you have taken a picture that you think is unique and valuable — let’s say a picture of a jaguar darting out from a Mexican jungle. The jaguar has now disappeared, so you are never going to get that picture again in your life, and you really care about it. (I am trying to make this example comparable to a human being, for we say that every human being is uniquely valuable.) You pull the tab out and as you are waiting for it to develop, I grab it away from you and rip it open, thus destroying it. When you get really angry at me, I say blithely, ‘You’re crazy. That was just a brown smudge. I cannot fathom why anyone would care about brown smudges.’ Wouldn’t you think that I were the insane one? Your photo was already there. We just couldn’t see it yet.” (Richard Stith, “Does Making Babies Make Sense? Why So Many People Find it Difficult to See Humanity in a Developing Foetus,” Mercatornet, September 2, 2008.)
As pro-life philosopher Scott Klusendorf notes, “The science of embryology is clear. From the earliest stages of development, the unborn are distinct, living, and whole human beings. Therefore, every ‘successful’ abortion ends the life of a living human being.” (Scott Klusendorf, The Case for Life, Crossway Books, 2009, p. 35.)
Embryologists, who are the experts in the field on human embryos, consistently agree that the unborn are alive and human from fertilization. Consider the following from the most-used textbooks on the issue:
“Although life is a continuous process, fertilization (which, incidentally, is not a ‘moment’) is a critical landmark because, under ordinary circumstances, a new genetically distinct human organism is formed when the chromosomes of the male and female pronuclei blend in the oocyte.” (Ronan O’Rahilly and Fabiola Muller, Human Embryology and Teratology, 3rd ed., New York: Wiley-Liss, 2001, p.8.)
“A zygote is the beginning of a new human being (i.e., an embryo).” (Keith L. Moore, The Developing Human: Clinically Oriented Embryology, 7th ed., Philadelphia, PA: Saunders, 2003, p.2.)
There are many more examples I could give. In short, you didn’t come from an embryo, you once were an embryo. Sophisticated pro-choice philosophers also know that human life begins at fertilization:
“It is possible to give ‘human being’ a precise meaning. We can use it as 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.” (Peter Singer, Practical Ethics, 2nd ed., Cambridge: Cambridge University Press, 1993, pp.85-86.)
“Perhaps the most straightforward relation between you and me on the one hand and every human fetus on the other is this: All are living members of the same species, Homo sapiens. A human fetus after all is simply a human being at a very early stage in his or her development.” (David Boonin, A Defense of Abortion, Cambridge University Press, Cambridge, 2003, p. 20.)
In fact, Alan Guttmacher, former president of Planned Parenthood, in 1933 (a full forty years before Roe v. Wade was passed), wrote:
“This all seems so simple and evident that it is difficult to picture a time when it wasn’t part of the common knowledge.” (Alan Guttmacher, Life in the Making: The Story of Human Procreation, New York: Viking Press, 1933, p. 3.)
Additionally, a Planned Parenthood brochure from 1964, when answering a question about whether or not abortion is birth control, states: "Absolutely not. An abortion ends the life of a baby after it has begun."
In my next article, I will address objections to biological humanity from fertilization. But the facts of science are clear: human life begins at fertilization.