Ah, I think I see the issue. I’ve heard of autoregulation within cells, or systems (renal, cardiac, etc.) but I’ve never heard anyone use the term at the organism level. Ok, well, in that case, you’re correct that some of the fetus’s *systems *are autoregulating. But then I’m back to, “so what?” and “how is that a thing that distinguishes a zygote from a heart muscle cell or a kidney and makes it wrong to remove it?”
I still maintain that it has nothing to do with the cells around the zygote that attach to the endometrium. No matter how you look at it, those are not and never will be cells in the embryo’s body. The zygote/embryo is, for this short period of development, completely a passive passenger in the pod.
Let’s take a look back, 'cause I’m starting to forget what we’re actually talking about. We started with an attempt to justify calling a fertilized egg a child, and why it’s scientifically and morally the same as a child, correct?
[QUOTE=http://boards.straightdope.com/sdmb/showpost.php?p=16530500&postcount=229]
Let’s see: 50% your DNA + 50% dad’s DNA, growing in your body by it’s own processess = child.
[/QUOTE]
So it was pointed out that, no, it doesn’t grow “by it’s own processes,” but rather needs a lot of mom’s processes to grow and mature.
So then we got:
[QUOTE=http://boards.straightdope.com/sdmb/showpost.php?p=16533446&postcount=242]
Let’s see again:
a) Home sapien sapiens DNA? Check.
b) Growth processess self-regulated? Check.
c) 50% DNA came from you? Check
d) 50% DNA from dad? Check
We have a winner: IT’S YOUR BABY!!!
[/QUOTE]
So we’ve moved from “by it’s own processes” to “Growth processes self-regulated,” except that they still aren’t. Mom’s body is needed to regulate the growth and development of the fetus.
Then the goalposts moved into Bizarroland for a bit:
[QUOTE=http://boards.straightdope.com/sdmb/showpost.php?p=16534583&postcount=252]
Fetuses are autonomous, their development is self -regulated.
[/QUOTE]
“Autonomous”? That’s seriously hilarious. Toddlers aren’t autonomous. Heck, my 20 year old isn’t entirely autonomous.
And then we got into this weird stuff about the embryo clinging to the uterine wall like a lost astronaut and “controlling” implantation. Which, again, it doesn’t. The embryo is a bunch of cells *inside *a sphere of cells (these all used to be one cell, but they’re sharply divided now into fetal cells and placenta/sac/yolk sac cells). Molecules on the exterior sphere meet complementary molecules on the endometrium and get stuck. Nothing is steering the ship, nothing is making it go faster or find a good parking spot. Nothing is directing it in any way except gravity, the shape of the mother’s uterus and currents in the fallopian tubes and uterus created by the mother’s fallopian cilia.
No, lock and key isn’t a great analogy, but it’s an easy analogy. In reality, there’s no director of the interaction, neither a tab nor a slot, a key nor a lock to be master of the process. It’s like mixing milk and vinegar - it curdles. It curdles whether you’re pouring milk into vinegar or vinegar into milk. Neither the milk nor the vinegar directs the process, it’s simply the result of an interaction of two substances.
Lots of the processes during pregnancy the result of an interaction between two bodies. But implantation is just chance and chemical reactions. Nothing’s directing it at all, much less a child.