Human Life Begins at Fertilization

I’d like to thank e.gibson for being willing to debate an important scientific topic with me: does human life begin at fertilization? I should have started with some basic definitions, but thankfully e.gibson correctly understood the meaning of my words. For clarification’s sake however, I’ll define some of the more important words here:

• Chromosomes: Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. Each chromosome is made of protein and a single molecule of deoxyribonucleic acid (DNA). Passed from parents to offspring, DNA contains the specific instructions that make each type of living creature unique.[1]
• DNA: DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms.{2}
• Sperm and Oocyte: Male and female sex cells, respectively.
• Zygote: e.gibson defined “zygote” based on the Google definition: “a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.”[3]
• Embryo: in humans, the developing organism from fertilization to the end of the eighth week.[4]
• Fetus: In humans, the unborn young from the end of the eighth week after conception to the moment of birth, as distinguished from the earlier embryo.[5]
• Organism: I’ll take e.gibson’s lead, and use Google’s definition,[6] which is comparable to embryology textbooks: 1: An individual animal, plant, or single-celled life form. 3: A whole with interdependent parts, likened to a living being.

Note that a one-celled individual animal can be an organism.

Noted embryologists O’Rahilly and Muller place the beginning of the life of a new organism at fertilization:[7] "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."

The human entity at this stage has at least two key characteristics:

1. A unique DNA fingerprint: Each of the entity’s cells has a unique, complete genome of 46 chromosomes (unless there is a chromosomal anomaly like Down syndrome, in which the child has 47 chromosomes).
2. Whole human organism: The only thing this entity needs is a proper environment and adequate nutrition to develop herself as an individual member of the species. There is no substantial change in the human organism from fertilization until death. It is an organism whose development is being driven from within. It is developing itself to the next stage of the organism according to the nature of the organism. The organism is also integrating its body parts for the good of the whole. This is what distinguishes the zygote from other somatic cells.

E.Gibson makes the biological mistake of confusing parts with wholes when he classifies the zygote as mere cells, instead of as an organism. As Scott Klusendorf points out in his book, The Case for Life,[8]

"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. True, it's an immature human, as is an infant, but it's a whole human organism nonetheless...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."

Some questions for my opponent on species classification:

1. At what point in development do you believe a zygote/embryo/fetus becomes a member of the human species?
2. What was it before?

I’m going to close by quoting some of the other top embryology textbooks now, as well as the most respected pro-abortion-choice philosophers in the world today. I realize that appealing to scientists or philosophers is not in itself an argument. They have studied these things and they should know, but they could also be mistaken. But I’m going to need some actual evidence that shows all the embryologists and pro-abortion-choice philosophers are wrong. Drawing a mistaken conclusion from a 9^th grade textbook isn’t going to cut it.

Modern Teaching Texts on Embryology

"Human development begins at fertilization, the process during which a male gamete or sperm unites with a female gamete or oocyte (ovum) to form a single cell called a zygote. This highly specialized, totipotent cell marked the beginning of each of us as a unique individual."[9]

"A zygote is the beginning of a new human being (i.e., an embryo)."[9]

"[The zygote], formed by the union of an oocyte and a sperm, is the beginning of a new human being."[10]

"Human embryos begin development following the fusion of definitive male and female gametes during fertilization... This moment of zygote formation may be taken as the beginning or zero time point of embryonic development."[11]

Pro-Abortion-Choice Philosophers

Peter Singer: “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.”[12]

David Boonin: “Perhaps the most straightforward relation between you or me on the one hand and every human fetus from conception onward 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.”[13]

Sources:

1: http://www.genome.gov...

2: http://ghr.nlm.nih.gov...

3: http://bit.ly...

4: http://bit.ly...

5: http://bit.ly...

6: http://bit.ly...

7: Ronan O'Rahilly and Fabiola Müller, Human Embryology and Teratology, 3rd edition. New York: Wiley-Liss, 2001. p. 8.

8: Klusendorf, Scott. The Case For Life, 1st ed. Wheaton, IL: Crossway Books, 2009. 38. Print.

9: Keith L. Moore, The Developing Human: Clinically Oriented Embryology, 7th edition, Philadelphia, PA: Saunders, 2003. pp. 16, 2.

10: Keith L. Moore, Before We Are Born: Essentials of Embryology, 7th edition, Philadelphia, PA: Saunders, 2008. p. 2.

11: William J. Larsen, Essentials of Human Embryology, New York: Churchill Livingstone, 1998. pp. 1, 14.

12: Peter Singer, Practical Ethics, 2nd ed. (Cambridge: Cambridge University Press, 1993), 85-86.

13: David Boonin, A Defense of Abortion, (New York: Cambridge University Press, 2003), p. 20

I’d like to thanks e.gibson again for debating this issue with me. I will spend this round rebutting his arguments and I’ll conclude with my closing remarks.

Con’s fundamental mistake is that he assumes that until an organism can be classified as a member of a certain species, it is not a member of that species! Remember, my fundamental argument is:

“By the end of the fertilization process, (instigated by two human beings) what follows is this: a living, whole organism of the human species.”

Con’s response is that zygotes “do not meet the criteria for species classification. Therefore, they are not a member of the human species.”

Imagine the first biologists that classified this flying frog (Rhacophorus suffry) two years ago.[1] According to Con, the flying frog became a flying frog once it was classified, not once it was conceived! This is obviously false. Even though humans were not aware of this species of frog nor had we named it, the flying frog still existed in obscurity. It didn’t change species once we named it. It remained the same kind of thing it always was. All it had now was a name.

It would be really bizarre for us to staff biologists at every hospital delivering room, whose job it is to determine the species of a newborn baby. Why? Because we know that when two humans reproduce, a new human comes out. And that new human began her life as a human zygote, then developed into a human embryo, then a human fetus, and is now a human infant.

Con accused me of not rebutting his fundamental argument, because he thought I was trying to show that the organism is alive, something he had already agreed to, when in fact, I spent most of my round two demonstrating that a single-celled entity can be an organism, and that in the case of humans, we know that zygotes are members of the human species.

I don’t think Con did this on purpose, but I think it explains why he had such a low view of my round two. He thought I was ignoring his fundamental argument, when in fact I was responding directly to it.

Con points to Muntjac deer that have 46 chromosomes, arguing that having 46 chromosomes is not enough to characterize human beings. I agree. That doesn’t mean humans don’t have a unique DNA fingerprint. It simply means that some other animals also have 46 chromosomes in their unique DNA fingerprint.

Con states that I am “simply stating that zygotes bear the potential to become humans, one day.” That is not at all my argument. I believe zygotes are full members of the human species from the beginning of their life as an organism. I don’t think they change species somewhere down the road after they develop tissues. Zygotes aren’t potential humans. They are humans with the potential to develop themselves into older more developed humans.

I spoke of the zygote “developing itself,” because there has been some confusion in the abortion debate about whether the zygote develops itself like a Polaroid, or if the zygote is constructed like a car. Richard Stith wrote a great piece on this,[2] but I didn’t expand on this point because Con didn’t argue that the zygote does not develop itself.

My questions about species membership is not “irrelevant.” It’s directly to the point Con is making. I’ve made a case that the zygote is a human organism, which Con disputes because it doesn’t have tissues yet and thus can’t be classified. My question that if the zygote is not of the human species at the beginning of her life, “when does she become human” is completely relevant. Either you are the same species during the entire existence of your life, or you have the ability to change species during your lifespan. My opponent is arguing the latter. I’m just asking for some evidence.

Con accuses me of making pro-life claims in regards to abortion. Not at all. I have offered evidence from both embryologists, the true experts on this issue, as well as pro-abortion-philosophers on whether the zygote is a human organism. I quoted pro-abortion-philosophers because if anybody would want to dispute a human zygote’s species membership, it would be a pro-abortion-philosopher. Yet they virtually all admit that the zygote is a living human, and instead try to argue for abortion rights based on whether the zygote is a full person or not, or whether that zygote has the right to the mother’s body.

Con stands as a lone wolf against all the scientific evidence that the zygote is not just alive, but a living human organism, and refuses to believe it. I wonder if there is ANY level of evidence that would convince Con? I hope so, because if people from both sides of any issue can’t find common ground on the most elementary biological facts of the case, there is little hope of moving the discussion forward.

Luckily, unlike Con, all embryologists and the vast majority of pro-abortion-choice people can agree that scientific evidence shows that zygotes are living human organisms. Vote Pro.

Sources:

1: http://www.sciencedaily.com...

2 http://www.firstthings.com...

“That doesn’t mean humans don’t have a unique DNA fingerprint. It simply means that some other animals also have 46 chromosomes in their unique DNA fingerprint.”

-Once again, my opponent shows no other premises to indicate a “unique DNA fingerprint,” other than 46 chromosomes.

I will concede to Pro that human life begins to develop at fertilization. However, this is not enough criteria to biologically classify it as a member of the human species—by any stretch of logic.

To state that a group of cells bears some characteristics of a human being is quite different than saying the same cells are a member of the human species! To even say it could develop, in the future, into a human is still insufficient. This would be equivalent to looking at the blueprints for a skyscraper and saying, “Look! It’s a skyscraper!”

Incidentally, my opponent has stumbled upon a fascinating existential dilemma. He implies that essence precedes existence. Meaning, the organism being developed is simply fulfilling the abstract blueprint of an already designed creature. I’m sure that my opponent would argue that zygotes are simply fulfilling the cosmic order of things (i.e. God), therefore they are humans. Sartre would argue that man is “defined only insofar as he acts.”(1)

I do not believe that essence precedes existence. I believe that existence must precede essence because humans can only perceive an essence after they have, in fact, existed!

Contrary to Pro’s indication of my loneliness in this argument, many embryologists have never stated that the zygote is a full-fledged member of the human species. This is a misrepresentation. They have simply indicated that human development has begun at the zygote level(2). Pro reads that sentence, yet all he sees is “human” and “zygote.” My opponent hastily attributes his boldness in species classification to the entire scientific (and philosophical) community.

I wish to extend my sincerest thanks to Pro.

I petition you to vote Con, simply because Pro’s argument only leads to misrepresented science and failed logic.

References:

1. 1. http://en.wikipedia.org...


2. 2. http://www.princeton.edu...