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I often hear or read this statement:

"It's not a human, it's a fetus."

In other words, some think a fetus is non-human until a certain point.

And another similar statement:

"The fetus isn't alive until 26 weeks of gestation."

So some think the fetus is not actually "alive" until a certain point.

What does biology have to say about these two statements?

I encounter these statements often in discussions about abortion, but that issue, and other similar philosophical issues, are outside this question. I'm wondering strictly from a scientific/biological standpoint: are these statements true?

Is the fetus in a human mother non-human until a certain point?

Does the fetus not classify as "alive" until a certain point?

The people I encountered truly believed these statements (3 of the 4 in mind also claimed science was on their side), so it's not as if the question has no merit. I assumed that in the realm of science and biology, there must be a convincing and sure answer.

yamad
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JohnDubya
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    Define "alive". Because a fetus almost definitely is alive. Perhaps they meant it isn't sentient until that point? – John Dvorak Sep 18 '14 at 02:44
  • @JanDvorak, I have no idea what the person meant by "alive." I copied and pasted these statements from actual quotes as representations of general ideas I often encounter, but I don't know in what way they were using the terms. – JohnDubya Sep 18 '14 at 02:46
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    Do you have any specific sources for these claims? To me it sounds like someone is trying to justify something they shouldn't. – John Dvorak Sep 18 '14 at 02:47
  • I have never received sources from anyone claiming either of these things. I personally do not agree with the statements, but I would rather those with expertise in biology speak clearly to the statements. Again, I have run into these statements so many times, I thought it wise to gain more understanding from those more versed in this area. – JohnDubya Sep 18 '14 at 02:59
  • MAYBE one possible 'indicater' of something being 'alive' is the ability for 'it' to move or 'change' itself in some 'way' that does not involve any 'help' or 'resources' from an 'outside' source. Note a fetus can move it's arm or 'kick' independently of it's Mother. However many philosophers have tried to argue 'within' adults there is no mind; we are just neuro-mechanical 'robots', so by this definition we adults are not 'alive' (just like robots are not alive)! – user128932 Sep 18 '14 at 06:27
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    You need to clarify what you are asking here: 1) The human foetus is of course human, it's not a bird, sunflower, donkey or other. 2) The foetus, by definitions of life that I've seen, is probably classed as "living" but that could be debated. 3) It may appear that you are interested in whether or not the foetus is concious, aware, intelligent, able to process independent thoughts feelings and emotions, or sentient (judging by the quotes you've put in) - I don't think that belongs here so you should clarify that a little so people answer the first two points but not the third. – rg255 Sep 18 '14 at 09:49
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    I feel like you are trying to get confirmation by biologists of your side of a moral, ethical, philosophical or political question. To do so, you have paraphrased your opponents' point of view in a way that might caricature or 'straw-man' them. The fact that you can't point to any place these specific statements have been made reinforces this suspicion. If you think that an answer based on a narrow biological reading of these statements will prove something about the wider question you are wrong. As questions about biology they are pointless and uninteresting. –  Sep 18 '14 at 10:23
  • Might you have mistaken "... alive until 26 weeks of gestation" for "... a life until 26 weeks of gestation". The latter does at least have a meaningful interpretation; the former does not - a growing foetus can't be anything other than alive, but whether or not you consider it a life is an arbitrary distinction, and one subject to much philosophical pondering, all of which is off-topic here. – 410 gone Sep 18 '14 at 11:44
  • It depends. My little finger is certainly "alive" and "human". But I wouldn't expect it to last long on its own, and I'm pretty sure no one would interact with it as a "human" if they found it on a sidewalk. – user2338816 Sep 18 '14 at 11:56
  • @JohnWasham I don't see where you previously said that these statements are from a discussion you had last night. Rather you said that you 'often hear or read' these statements. –  Sep 18 '14 at 13:21
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    @jwg, as I mentioned in my previous comment, these are exact quotations of a discussion I had last night (comments from Joji-chan at 8:37pm and from AKAMrWobbels at 9:07pm on https://plus.google.com/b/118125465432602950506/113663424599392189408/posts/6XTbtDrdY3v ). It is quite frustrating to me that in spite of my intentional avoidance of personal opinion in the question, you have read opinion into the question against my wishes. Sigh. – JohnDubya Sep 18 '14 at 13:22
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    @JohnWasham I understand that you are pretending to ask a neutral question about objective facts. My point is that you actually aren't. You are trying to move a Facebook debate onto a site which isn't the right place for it. –  Sep 18 '14 at 13:23
  • @jwg, is there a right answer here or not? I figure there is, which is why I asked the question. Did I ask for someone to come and back me up on something? How is this not clear? I asked the question and left it for someone smarter than me to answer. Your jumping to conclusions is quite frustrating. – JohnDubya Sep 18 '14 at 13:24
  • @GriffinEvo, here is the man's full quote: "Well the fetus isn't alive, based on elementary principles of organismal biology (i.e. Bio 100), until 26 weeks of gestation, so what else is it if not non-living human tissue that develops into a living organism, known as a human, at 26 weeks of gestation?" That was his claim, so I simply asked the question to figure out if his claim was valid. I think you would agree he did not seem to be claiming your 3). He legitimately thought the fetus wasn't alive. What he meant by "alive," I'm not sure. – JohnDubya Sep 18 '14 at 13:39
  • Although I don't necessarily like the question, I don't see anything wrong with it. Fetal stage is generally accepted as beginning at the eleventh week in gestational age, which is the ninth week after fertilization. – rhill45 Sep 19 '14 at 03:16
  • @yamad, thank you for wording the question better! – JohnDubya Sep 19 '14 at 14:25
  • @JohnWasham I understand your frustration, but feel that a couple of clarifications/definitions are needed in the question to make it answerable. However, the answer might then be rather self-evident. First, I would like to see a definition of "human" (as used here). I assume that you are going for "human" as in "belonging to the human species". Also, the term "alive" probably means "cannot live independently". I understand that this vagueness is caused by the person making these statements, probably to use a highly charged term ("alive") to drive home a point and win an argument. – fileunderwater Sep 23 '14 at 09:04
  • The vagueness of the terms is also shown in how you have worded the question. In the title you write "..a human fetus is considered...", but in the first statement the terms "human" and "fetus" are used as incompatible opposites (""It's not a human, it's a fetus.""). Your title is also basically a tautology (if not, the use of human is vague): "Do biological facts determine when a human fetus is considered ... human?". – fileunderwater Sep 23 '14 at 09:22
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    Life, human, and human life are being used interchangeably, but they're not interchangeable terms. The empirical terms "Alive" (has measurable ribosomal activity for example), and "human" (DNA testable) cannot be compared to "human-life" (philosophical subjective definition). If we are talking about "is a fetus a human-life?" then the question is off topic. If the question is "is a fetus human and alive?" then we can answer it (and @Susan's answer is a good answer at that!) – James Jul 12 '15 at 11:09

2 Answers2

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Life is generally distinguished from non-life by metabolism and growth. As such, a fetus is alive. The reference to "not...until 26 weeks gestation" that you've heard likely refers to viability.* With the most aggressive medical care, this is the approximate age when a fetus may be able to survive outside the womb.

The term human from a biologic perspective is a species label.** Given that a fetus is genetically indistinguishable (in broad strokes) from a post-natal human, I think it would be hard to argue that it is anything other than human.

Summary: Yes, a human fetus is both alive and human.

*Note that this use of the word viable is standard but deviates somewhat from the etymology of the word.
**I'm ignoring here other ancient species (homo-) which may be considered human but are irrelevant to the question.

Susan
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  • on the other side of things, there are many things that are alive which have different levels of priority. our feces is also alive. a sneeze is full of life. So you want to also think about that. Life is amazing, but also very common in the everyday. – shigeta Sep 18 '14 at 03:49
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    @shigeta - I'm missing your point. Bacteria in feces are alive, no doubt. Bacteria in the nasopharynx that may be expelled with sneezing are alive, no doubt, as is the creature doing the sneezing. How is that related to this question/answer? – Susan Sep 18 '14 at 03:59
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    Note that the question is not whether the foetus is human (adjective), but whether it is a human (noun). It's an important difference, and takes us out of biology and into philosophy and ethics. – 410 gone Sep 18 '14 at 11:41
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    @EnergyNumbers - mmm, not sure I agree with that distinction, but I do agree that it's not a great question for this site, not because it's un-answerable but because the answer is extremely simple (when limited to biology). I don't have enough rep to VTC, so instead I answered it as best I could within the scope of the site. – Susan Sep 18 '14 at 12:31
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    I think the point is that the question almost certainly comes from the context of the abortion debate, i.e. whether killing a fetus should be a right or a crime. In that regard, whether a fetus is alive does not matter much, since we necessarily kill many things that are alive without giving it a thought. – Michael Borgwardt Sep 18 '14 at 12:53
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    @MichaelBorgwardt, you are correct. The statements in the question were copied and pasted from two commenters last night in a discussion about abortion, but I intentionally left all opinion out of the question and no mention of abortion. The man who claimed "the fetus isn't alive" said that statement was "Biology 101." So while you and others may view this question as too simplistic, it obviously isn't to some people. I decided to let those who really know biology speak to the truth of these statements. – JohnDubya Sep 18 '14 at 13:32
  • @Susan, thank you for the simple and concise answer and for the sources. – JohnDubya Sep 18 '14 at 17:32
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    When I read this question, I immediately knew it was a consequence of a debate on abortion. A biologist who supports the right to choose abortion would carefully make a distinction between the definition of something that is alive and human (like a zygote, or even the sperm and egg) and a human being (in other words, a person). – Joe Z. Sep 19 '14 at 14:42
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The fetus is certainly "alive" from the very beginning, since conception. The second comment hence does not make sense.

Regarding whether it is "human" or not, that would depend on the definition of "human". It seems to be more a philosophical than biological question. From the biology point of view it all goes down to this, a fetus in a human womb is a "human fetus", certainly not a "mouse fetus". Fetus only indicates a time period in the development of a mammal (before being born). Another question is whether the fetus has attributes of grown up humans, like the ability to talk. But then, a newborn does not have many of those attributes yet it is considered a human.

ddiez
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  • To think of it, fetus leads a parasitic life till it is born. – WYSIWYG Sep 18 '14 at 06:18
  • @WYSIWYG But note that a newborn human is also unable to survive without an adult caretaker. – Susan Sep 18 '14 at 06:24
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    Any definition of "human" someone tries to use besides this one (that it is human regardless of how far through gestation it is) will almost certainly end up excluding some "obviously human" segment of the population. This answer is very well-worded. – David L Sep 18 '14 at 06:59
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    @WYSIWYG But a parasite does so without the host consent and is recognized by the immune system as a threat. A female mammal sacrifices herself in order to provide the environment for the proper development of the new organism, until it is able to survive outside. – ddiez Sep 18 '14 at 07:00
  • @ddiez a female can get pregnant without her consent. Parasite need not be detected by immune system- immune system is just a hurdle to its parasitic lifeform. Plus, fetuses can also invoke immune responses. Parasitism is a way of life in which one individual thrives at the cost of other. – WYSIWYG Sep 18 '14 at 08:24
  • @ddiez IIRC, mother's immune system only recognises the fetus after it settles down in the womb wall and starts producing a hormone (essentially an immunosuppressor, IIRC) into the mother's bloodstream. Until then it's just a foreign body. – John Dvorak Sep 18 '14 at 08:27
  • @Susan. well yes but that's strongly true for human babies. My statement was general. Moreover a newborn is not a parasitic anymore. The adult has a choice to abandon the baby (though it sounds harsh). – WYSIWYG Sep 18 '14 at 08:27
  • @WYSIWYG no sane person would ever do that, though (Yes, I'm well aware this is a statement about the sanity of mankind) – John Dvorak Sep 18 '14 at 08:29
  • @JanDvorak.. yeah.. and some pathogens also elicit responses that allow them to escape the immune system. – WYSIWYG Sep 18 '14 at 08:29
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    A parasite escapes the immune system. The mother enables the fetus to grow in a immune tolerant environment. Organisms reproduce to perpetuate the species. This is one of the defining characteristics of life. Note that parasite has a harmful connotation and typically (if not always) involves different species. I do not think it correct to consider the fetus a parasite. – ddiez Sep 18 '14 at 08:47
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    @ddiez You can see this post. Some discussion about the definition of parasitism. Whatever be the initial turn of events, the fetus is actually eating the nutrients from the mother depriving her of those. Mother chooses to eat more and let the fetus grow for lets say some greater good; that doesn't change the nature of this interaction. The terms escapes or enables are just literary; mechanistically there is no difference. – WYSIWYG Sep 18 '14 at 09:44
  • And I didn't actually state that fetus is a parasite. I just raised an opinion. You see, pregnancy is always a burden for the females. My point was- if you consider a fetus "alive" then it is a parasite. Otherwise you can call it some congregation of cells that is catalyzing the process of reproduction. Cell cycle in a bigger scale!! So imagine a unicellular organism- you won't call the cyclins and newly replicated DNA as life, right? We can continue this discussion on chat because this can go very very long as it is just exchange of opinions – WYSIWYG Sep 18 '14 at 09:52
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    In fact, by pretty much any sensible definition, the unfertilized ova and sperm are also just as alive as the fertilized embryo is. Just because these haploid gametes make up a relatively small part of the human life cycle doesn't change the fact that they move, they metabolize, and, crucially, they're capable of reproducing (by first fusing into a diploid zygote, which then grows and produces more gametes). Or, as somebody once quipped, "a chicken is an egg's way of producing more eggs." – Ilmari Karonen Sep 18 '14 at 11:29
  • @IlmariKaronen, don't unfertilized ova and sperm carry the same DNA of their host? And aren't fertilized embryos wholly separate and distinct life forms from his or her mother? I was of the understanding they have their own set of DNA and are, at the point of conception, a completely separate human life form. That seems much more of a distinction than your comment describes. – JohnDubya Nov 13 '14 at 00:45
  • @JohnDubya: Each ovum or sperm cell carries half the DNA of the parent that produced them; when an ovum is fertilized, the resulting embryo inherits half its DNA from the ovum, and half from the sperm. An ovum or a sperm is thus equally related to the parent that produced it, as to the child produced from it. If you consider the child "wholly separate and distinct" from the ovum, then, by the same argument, you should also consider the ovum "wholly separate and distinct" from the parent. (Well, almost. Relatedness gets a little tricky when ploidy changes, as notably seen in social insects.) – Ilmari Karonen Nov 13 '14 at 12:02
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    @JohnDubya: ... In any case, my point wasn't about whether, or to what extent, sperm and ova are distinct from the diploid life stages preceding and succeeding them, but about whether they count as "alive". It's very hard to come up with an objective definition of "a distinct living organism" that would exclude a human sperm cell without also excluding, say, a drone bee. – Ilmari Karonen Nov 13 '14 at 12:08