I appreciate Cecil’s attempt at simplifying the question and avoiding an ethical conclusion…but here are a couple of things to consider, fact-wise: 1) life is a continuum – the ovum and sperm are no less alive apart than they are together as the fertilized egg (i.e. the embryo) 2) the egg is fertilized in the fallopian tube a few days before implantation and at this stage has an extra set of chromosomes – the polar body; this is extruded only after fertilization and if retained can lead to genetic mutations 3) if the soul enters the embryo at fertilization, does it also split when twins are made?
It’s been awhile since I last studied meiosis, but isn’t the polar body a separate haploid cell, already divided from the ovum? ::scrapes rust off memory banks::
“Life” and “alive”, I think, are less objectively discernable conditions than value judgments or philosophical constructs, much like “soul”.
If one was to read the Christian Bible, the answer is simple & would probably shock 99.999% of people who think they have read the Bible, including Popes.
Genesis 2:7 “And God breathed into the form the breath of life and man became a living soul.”
No breath, no soul, no person. A surprising number of religions concur with this position and in many legal jurisdictions, air in the lung sacks is considered proof of a live birth.
I’m more inclined to the brainwave concept, but that would disallow so many things that walk on their hind legs.
Metaphor. Anyway, what I really want to know is what the hell is going on in the picture. This is probably the least parseable illustration I have seen here.
The couple just finished coitus and the doctor is immediately congratulating them as the OB normally does after giving birth: Congratulations, it’s a blastocyte!
goodma82, welcome to the Straight Dope Message Boards, we’re glad to have you here. When you start a thread, it’s helpful to other readers if you provide a link to the column you’re discussing. Yeah, it’s on the front page today, but in a week or so it will fall back into the massive archives, so providing a link saves searching time… and helps keep us all on the same page.
No biggie, you’ll know for next time, and, as I say, welcome!
There are three polar bodies for every eventual ova. The first two are lost before ovulation, but the ovulated body still has 46 chromosomes. Only after it’s fertilized by a sperm does it pinch off it’s final polar body with half the chromosomes from the nucleus, and then the sperm’s haploid* nucleus meets up with the ova’s haploid nucleus.
There is a very controversial theory being bandied about that sometimes that final polar body is fertilized by another sperm and develops as well, leading to “half-twins”. Critics point out that the polar body is extremely undersized in comparison to the ova, and that it wouldn’t have enough nutritional cytoplasm to keep the blastocyte alive long enough to implant.
*And, of course, we all remember that the H. In Jesus H. Christ stands for “Haploid”, since he only had DNA on his mother’s side, right?
Of course, we are talking about a presumably rare occurence, here. It could just happen in those cases where the polar body happens to be unusually large for some reason.
As to the OP’s point, yes, all of the precursor germ cells are alive, but before fertilization, it’s harder to identify them as a separate organism. Once fertilization occurs, you have something with a distinct genome from either parent, which could be justification for calling it a separate life, rather than just a part of one of the living parents.
Could be, sure. I just wanted to mention why it’s not a widely accepted theory yet. And, really, I can’t quite figure out why it would be a big deal, except that finding out what we thought was impossible isn’t is always kinda cool. “Half-twins” wouldn’t be genetically any closer than fraternal twins as we currently understand them, since half the genes went with the egg and half the “polar body” and two different sperm fertilize - it’s not like they get *identical *genes from the maternal meiotic division. They’d go on to form two placentas and two amniotic sacs, and be indistinguishable from fraternal twins, wouldn’t they?
In fact, now that I think on it, they’d be slightly *less *“related” than regular siblings, since they can be counted on not to have *any *of the same maternal genes. If Mom had, for a very simple example, one B and one b gene, then under normal circumstances, more than one kid might get a B gene from two different eggs. But because the B and b split at this last meiosis, “Half-twins” would always get different ones, one B and the other b, one A and the other a, etc.
A while back an enterprising young college student in Louisiana advanced that argument after the state declared that life begins at conception. He wanted to be allowed to purchase alcohol. Alas, fortune did not smile upon him.
Not to mention that, you know, the first human as per the Bible was created whole and adult from dust. I think it’s pretty fair to say the rules would be different for Adam.
