As with all ethical/moral arguments, there’s a lot to discuss.
Firstly, on the point you’ve raised several times: no, a medical abortion does not — technically — act on the foetus. The most common medical abortion is a misoprostol/mifepristone kit. The first drug causes the woman to stop producing hormones necessary to continue the pregnancy, causing the termination of the foetus. The second drug induces labor, causing the woman to expel the now-defunct pregnancy. There are no “chemicals to burn” as you put it, this is an unfortunate piece of propaganda spread by the anti-abortion movement.
Life Is A Useless Term
You’ve talked a lot about “life” and when it begins. There’s a problem with using this term, as technically every cell is “alive” — how can “life” begin at conception if the sperm and ovum are both “alive” themselves?
This is why, when we discuss abortion, it’s much easier to use the idea of “personhood”. It’s not, as the source you cited claims, a dodge by abortion advocates, but rather a more useful way of defining what is important to us about humans. “Life”, in and of itself, isn’t valuable to us. Algae is alive, but no one is arguing that it deserves the same moral status as a human being.
No One Cares About DNA
Anti-abortion arguments often center around the idea that conception is important because it creates a piece of unique DNA. This is a logically inconsistent reason to disavow abortion. Melanoma cells in a petri dish meet every criteria you’ve specified: unique DNA, human, alive — they could even (potentially) become a baby with our current technologies. And yet no one would argue that killing these cells is unjust. Thus, it is clear that none of these factors are actually moral issues.
Another way to look at it is this: if unique DNA is a requirement for us to consider someone a “person”, then identical twins are not people. Since this is obviously not a moral position, it’s clear that unique DNA is not a factor in our definition of personhood.
Everything Is A Gray Area
Ultimately, every argument comes to the same place. The uncomfortable truth is that there is no single, easily-definable place that we can point to and say “That’s a human being. That’s a person”. Using the anti-abortion argument you cite (SLED), you could easily include sperm cells and ova in your definition of people. What are they, but children at a lower stage of development, not yet fully-formed and still vulnerable? What are my cheek cells, except a person who has not yet been ‘cured’ by scientists in a lab? Why should a few extra steps — even expensive ones — prevent them from being born? We don’t deny healthcare to sick children, after all.
The point is not that my cheek cells are people, but that defining what we believe to be a person isn’t easy. Anti-abortion proponents almost universally use conception because that feels like a black-and-white answer — before, just two random cells, after, a new life. But the point is that, scientifically, there’s not really any differentiation between a zygote and any other cell. So people are forced to make meaningless distinctions — unique DNA! — to justify what is basically a religious argument.
And, to be honest, no one really values zygotes as people. You don’t see “pro-life” people picketing IVF clinics, and they kill more zygotes than any women’s health service. I wrote a whole article on strategies that, unlike banning abortion, would likely decrease the number of zygotes that die each year. And yet, none of these strategies are embraced by the anti-abortion movement.
Obviously, zygotes possess “life”. This is, unfortunately, a useless quality for a moral decision, as it is shared by bacteria, algae and the like. Equally obviously, zygotes are not “people” in any meaningful sense.
In human development, there are no black and whites.
All we can do is try our best with shades of gray.