@KaptinKool – “I think that as a human race we can agree that there are many reasons that human DNA is more valuable than any other DNA. To begin with humans are the only organism where we have observed first person consciousness. This is important because we know that human life has intrinsic value beyond a simple will to survive. Whereas you may argue that that is the root of everything we do, humans have developed emotionally to a point where we observe life as meaningful and act not solely out of a will to survive but out of a will to enjoy our survival. We value not only our life but the lives of others, and a fetus is a potential human that shares our DNA, why would it be excluded from the right to life that it would gain 9 months later after birth. I would like to hear why a baby that has been just born would have more claim to life than a fetus that will be born as long as its mother doesn't kill it prematurely. Fetus' are human life set in motion as a consequence of peoples actions, whether or not it is fully developed is not important.”
Ok, firstly, by talking about “we”, meaning humans, you are already beginning an exceptionalism. Thus you are begging the question. Could a non-human intelligent life form argue similarly: we aliens only experience alien consciousness, therefore all aliens are better than all humans....
In addition, what stops the woman from saying that “my DNA is more valuable than my foetus’ because I am the only organism where I have observed first person consciousness”? Indeed, on any matter I can make that argument, and thus can justify my stealing somebody else’s medicine (my DNA is more important than his)
Though not a biologist myself, I can say with confidence that your wish to distinguish between human DNA and animal DNA in general, but not to distinguish between one human’s DNA and another’s is very weak.
I think probably the strongest thing you can do for your position is to say that the human DNA is not the important factor. If that is what makes the foetus human, let me introduce some other humans to you, just to illustrate:
1. Gestational choriocarcinoma
Here we have a fertilised egg, with human DNA. However, it does not develop into an embryo or foetus, but rather develops into an undifferentiated invasive and metastatic cancer (in the uterus and brain, pictured in the links below). Nothing else is produced, and ultimately this tumour will kill the mother if left untreated. Under your system, because this has human DNA, and specific human DNA too- only this tumour has that DNA, this tumour is a human, and we should consider it to have intrinsic worth.
http://museum.med.monash.edu.au/pics/S3U3.jpg
http://www.uphs.upenn.edu/path/web_docs/p200/GYN200/GYN0408.jpeg
2. Hydatidiform mole (aka molar pregnancy)
Again, a zygote that never develops into a foetus; instead, as pictured, it develops an undifferentiated mass of foetal tissue, often causing potentially fatal eclampsia. It also can become cancerous, since it sometimes develops into choriocarcinoma.
Of course, if human DNA is all important, this fine fellow is to be protected:
http://embryology.med.unsw.edu.au/Notes/images/week2/hydatidiformmolelabel.jpg
http://www.uphs.upenn.edu/path/web_docs/p200/GYN200/GYN0405.jpeg
3. Scleroderma
Last one, this is an autoimmune disease. The patient suffers from fibrosis (excessive scar tissue) in various parts of their bodies, including skin, heart, lungs and muscles. Analysis of the blood of patients with this tissue tissue shows that it has foetal monocytes with human DNA distinct from that of the patient’s. We can know that it is foetal from the fact that it can have Y-chromosomes, which rule out a connection to the patient’s own mother. The immune response to this distribution of cells causes the terrible and incurable disease.
However, since these cells have human DNA, we should consider them intrinsically valuable.
The fingers of this patient are almost totally unable to move due to the scarring:
http://www.ecureme.com/atlas/data/dis_images/Scleroderma550_ab.jpg
This is actually the heart of a scleroderma patient. The white scar tissue has almost totally replaced the cardiac muscle.
http://www-unix.oit.umass.edu/~excs597k/carpenter/images/restrict.jpg
And this list is by no means exhaustive. Nor is it considering grossly ill-formed foetuses that are potentially dangerous and certainly unable to develop, but nevertheless, have human DNA.
Never mind your balance of harms argument for abortion in exceptional cases, you are still making the assertion that, if these things weren’t actually dangerous for the mother, say, merely uncomfortable, it would be morally wrong to kill them because they are as separate an organism as a foetus, and just like a foetus, have human DNA.
“Now for your second question, I am not a doctor and will not pretend to have a good idea of what is reasonable. All I would say is that if doctors agree that the woman is better off aborting for her safety (as in the chance of death is fairly imminent pending an abortion) then I would consider that as a plausible cause for abortion.”
You are evading the question. When I ask you to start talking about percentage chances of death, I am assuming the medical knowledge, and reducing it purely to the consideration of the relative values of the foetus’ life and the mother’s life. If it were a 1% chance that the mother dies, would that be enough for you to advise your wife to have an abortion?