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The whole bone marrow to sperm thing... - The Phantom Librarian
Spewing out too many words since November 2003
The whole bone marrow to sperm thing...
I know, tons of ethical questions here, but I'm not going to get into them. Lots of ways to go, and I fully expect SF writers to pick up the slack.

But here's what I'm wondering--why sperm? I mean, if you're going to start with something, why not start with eggs? It's not like men stop making sperm, but women do run out of eggs at a fixed time, and we can't exactly run to the corner store to buy more. Does anyone know? Is it just the complexity of the cell?
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rotae From: rotae Date: April 19th, 2007 02:50 pm (UTC) (Link)
It's so that women can eventually control the world, and just have men for sex slaves.

That's what I voted for, anyway. XDDDD :D

Sorry. That's a serious question. LOL. ^^; I dunno. Maybe it has something to do w/ there being more women than men in the world. LOL. >.> Ignore me... XDDD

fernwithy From: fernwithy Date: April 19th, 2007 02:56 pm (UTC) (Link)
Sorry... running out of eggs and getting desperate. ;)
rotae From: rotae Date: April 19th, 2007 03:06 pm (UTC) (Link)
LOL. Well, I dunno your current situation, but if you're still waiting on the right guy, you could always get one of those implants, which makes you stop releasing eggs. It's a kind of birth control. I dunno if that actually helps for that situation though... LOL.

Or you could freeze some of your eggs.

Or if you're trying to get pregnant now, then... I dunno. LOL.

fernwithy From: fernwithy Date: April 19th, 2007 03:07 pm (UTC) (Link)
I'm waiting for the right guy, and on a whim, I called my insurance company about egg freezing--it's not covered unless you're already in a relationship and having trouble getting pregnant. Dude, if I were in a relationship, I probably wouldn't freaking need it! Let's try some logic here, man.
rotae From: rotae Date: April 19th, 2007 03:11 pm (UTC) (Link)
I just thought that you and your partner might have been running out of time... Like I said, I don't know your situation ;)

Hmmm... well, I dunno. You could check out that implant thing. Ask someone who knows what exactly goes on. :)

fernwithy From: fernwithy Date: April 19th, 2007 03:06 pm (UTC) (Link)
Of course, we could go to the simpler theory: Male researchers. ;p
rotae From: rotae Date: April 19th, 2007 03:12 pm (UTC) (Link)
LOL. But doesn't the whole "we can now make sperm" theory suggest that men aren't needed as much now? LOL. :D

springdove From: springdove Date: April 19th, 2007 03:22 pm (UTC) (Link)
I hadn't heard of this until just now, and my mouth totally dropped open. Why the heck would they WANT to make more sperm? It's like you say...guys keep making it their entire lives, and we run out eventually (and even if we don't run out, as ours are present at birth, they get older and more unstable). I think your hypothesis about the complexity of the cell holds water. I think sperm are simpler cells than eggs. Of course, it could just be that, yes, men tend to think their sex is pretty wonderful, so why wouldn't people want more? :P But the simpler cell thing makes more sense to me. That, or perhaps the bone marrow cells are more similar in structure to a sperm than to an egg. *shrug* I'm rambling.

I'm assuming the eventual goal of this whole thing is to try to make other types of cells that can replace damaged cells (an alternative to the whole stem cell thing?). Do you know if this is the case? Or are they just doing this because they can?
fernwithy From: fernwithy Date: April 19th, 2007 03:35 pm (UTC) (Link)
Oh, it's definitely stem cell research--using adult stem cells from bone marrow instead of embryonic stem cells, so considerably less controversial than the topic usually is. But why this particular thing? I haven't picked up on that. I'd guess there's a lot of "Oo, shiny," going on, but of course they're not going to print that. It could help men who've been injured, I guess. But I'd think women would be a more common market.

It's interesting. In theory, if they could make both gametes, a woman could create a daughter for herself who isn't a clone but has literally only one parent--unless you want to count that parent's two parents, of course; I think, genetically, it would amount to carrying one's own sibling. Not that I'd want that--I want a man, dammit!--but it's interesting in a science fiction-y way.
tree_and_leaf From: tree_and_leaf Date: April 19th, 2007 04:11 pm (UTC) (Link)
Most science is based on the 'Ooh shiny' factor (otherwise known as ('Hm, no-one else has looked at that, I bet I could get funding') - or is that overly cynical?
ladyvorkosigan From: ladyvorkosigan Date: April 19th, 2007 05:46 pm (UTC) (Link)
I think maybe a bit - a lot of things don't appear to have practical implications at first but turn out to later. Or, in other words, it's based on "oooh, shiny," but we need people who can look at things and say "ooh, shiny," because their enthusiasm for the research translates into practical tech down the line.
tree_and_leaf From: tree_and_leaf Date: April 20th, 2007 09:21 am (UTC) (Link)
Oh, I didn't mean to imply it was a bad thing ;) I mean, I'm an arts major, so I can't very well object to people studying things tha aren't practical...
fernwithy From: fernwithy Date: April 19th, 2007 06:07 pm (UTC) (Link)
I don't think it's cynical at all--I consider "oo, shiny" to be a much more legitimate reason to do something than, "Hey, I bet there's a practical use for this."
arclevel From: arclevel Date: April 19th, 2007 11:01 pm (UTC) (Link)
In theory, if they could make both gametes, a woman could create a daughter for herself who isn't a clone but has literally only one parent--unless you want to count that parent's two parents, of course; I think, genetically, it would amount to carrying one's own sibling.

I haven't heard about this, so I need to look into before I could comment on why sperm or anything like that. However, just off the top of my head, trying to use both gametes derived from one person would, from a genetic perspective, be inbreeding of the highest order. If you took the magnitude of genetic badness from having kids with your cousin, and compared that to the magnitude of badness from having kids with your brother, this would be another full level worse. As I said, that's just off the top of my head, but I'm pretty sure that would be the case.

And continuing off the top of my head, "why sperm" could involve complexity of the cell, but more likely will involve complexity of the process -- that is, spermatogenesis vs oogenesis -- and how much we know about the controlling factors. Spermatogenesis happens pretty much constantly, as you said, and oogenesis only prenatally (with later maturation of oocytes leading up to their release in ovulation), so that may make the process much easier to replicate. Spermatogenesis may be less dependent on surrounding tissues than oogenesis as well, though IIRC from histology, they're both pretty dependent; for spermatogenesis, it may mostly just need the testosterone, while oocyte maturation may require more factors. The cyclical nature of oocyte maturation may make it less convenient, also.

As I said, I haven't read about this specific study yet, though, so all that should be taken with a sizeable grain of salt. :-)
fernwithy From: fernwithy Date: April 19th, 2007 11:26 pm (UTC) (Link)
Ah, but inbreeding is only really dangerous when there's a bad allele involved; presumably, if you were going to the trouble of genetic engineering on this order, that kind of thing would be taken care of.

But yes, it's hugely squicky, which is why I'm thinking about trying to find a story that uses it.
arclevel From: arclevel Date: April 20th, 2007 01:58 am (UTC) (Link)
But that would require you to know about the potential dangers of homozygosity of your genotype in *every single gene* (plus all the regulatory elements and such). I'm not so sure I find it squicky, actually, but from a genetic standpoint, it would usually be really, really bad, and it really wouldn't ever make anything better. I'm not saying it couldn't be an interesting sci-fi premise -- I'm sure it could -- but real-world plausibility, not so much.
persephone_kore From: persephone_kore Date: April 20th, 2007 03:42 pm (UTC) (Link)
*agrees* I'm not particularly squicked at all by the self/self thing either.

I wouldn't say it's entirely implausible as something that could work in the real world... eventually. It wouldn't necessarily be a disaster if you had good genes and an excellent understanding of the genome, and we may one day get that far. It might theoretically be possible to make a few improvements, if it so happened that everything on a given chromosome was neutral/good in duplicate. But that would be rare.

However, all the reasons you mentioned would normally apply and would probably make the process riskier and less efficient than cloning, which would probably make it generally very rare.

I suspect that it may not be obvious to a lot of people that getting stem cells to turn into eggs or sperm would be an entirely different process from going through and picking out, gene by gene, what features you want or should eliminate for safety, and neither ability implies the other. You could certainly assume both for a science fiction story, but it would be better to acknowledge them as separate processes.
fernwithy From: fernwithy Date: April 20th, 2007 03:58 pm (UTC) (Link)
Oh, yes, of course. I just assume that if they're at the point where they're doing that much genetic manipulation as a routine thing, they'd also be routinely screening for genetic body slams.
persephone_kore From: persephone_kore Date: April 20th, 2007 11:53 pm (UTC) (Link)
If they're doing self/self gametic reproduction, yes, they'd better be! *grins* But making sperm/egg from stem cells would be more... developmental manipulation? And a very different process. And screening for problems is different from actually managing to make a combo without problems turn up.

Of course, if you're doing this involving societal rejects, maybe they aren't actually as careful as they ought to be....

Odd point: If you're assuming enough tech and skill to pick and choose genes so the kid will be viable, you could probably also assume that you can trim up an X chromosome into a Y.
tree_and_leaf From: tree_and_leaf Date: April 19th, 2007 04:09 pm (UTC) (Link)
Actually , it was my understanding that although in theory men remain fertile almost to the end of their lives, in practice male fertility is actually declining, and that some men are either stopping producing sperm (as opposed to semen), or producing very low numbers of sperm, or sperm which is so damaged that fertilization of the egg is unlikely to take place. Infertility isn't solely a female problem, though I don't know how the figures compare to the frequency of pre-menopausal women having difficulty concieving.
ladyvorkosigan From: ladyvorkosigan Date: April 19th, 2007 05:47 pm (UTC) (Link)
That's a good point - I think there was also a recent study that said men's sperm could degrade over time leading to more risk of birth defects. (Although whether that would be a greater risk than artificially created sperm, who knows).
lucyparavel From: lucyparavel Date: April 19th, 2007 05:47 pm (UTC) (Link)
Hmm, I have no idea! It is a good question though. However, just had to link you to this. http://www.tvshowsondvd.com/newsitem.cfm?NewsID=7193 Voyagers out on DVD this summer. I'm just amused that it is finally happening after we talked about it--last week?

fernwithy From: fernwithy Date: April 19th, 2007 06:08 pm (UTC) (Link)
Oh, serendipity! This is good.
From: (Anonymous) Date: April 19th, 2007 06:48 pm (UTC) (Link)
i think tree_and_leaf has a good point about male fertility declining. its caused, amongst others, by the estrogen in the water, because of women taking birth control pills.

but about your question, i just think there is more research available about sperm cells, because they are easier to "harvest" than female eggs (and maybe you have a point about the male researchers). so its easier to work with sperm because they know more about it.
From: (Anonymous) Date: April 20th, 2007 09:44 am (UTC) (Link)
(Raises hand) Science moron here. Would you be so kind as to explain (in simple language, LOL) why women taking birth control leads to estrogen in the water? Wouldn't it be purified out like all other waste?

From: (Anonymous) Date: April 20th, 2007 11:03 am (UTC) (Link)
Well, the estrogen molecule is not easily broken down, because it's such a complicated molecule. Water purification focuses on the most common pollutions, that are easily broken down by bacteria. Estrogen is more difficult. They've realized that, and research is being done, but they haven't come up with anything useful yet (I think).
It's not just birth control though, there are more molecules that are pseudo-estrogenic (which means they act like an estrogen), e.g. DDT (the old pesticide).

Mieke (forgot to mention my name in the original post)
From: (Anonymous) Date: April 23rd, 2007 01:21 pm (UTC) (Link)
Thank you, Mieke!

From: (Anonymous) Date: April 19th, 2007 07:18 pm (UTC) (Link)
I would guess it's the complexity issue. Dredging up my limited biology, I'm pretty sure the egg is responsible for passing down more information - mitochondrial dna or something. And I think the process of fertilization is largely egg-governed, whereas sperm subscribe more to the "reproductive success through large numbers!" tactic. So my guess it probably just has to "do" too much stuff to make eggs as easy as sperm to research.
torturedbabycow From: torturedbabycow Date: April 19th, 2007 07:19 pm (UTC) (Link)
(oops, wasn't logged in)
jetamors From: jetamors Date: April 19th, 2007 10:19 pm (UTC) (Link)
In order to get a stem cell to turn into what you want it to turn into, it has to be exposed to different conditions. For example, some of the cells of your immune system develop entirely in your bone marrow, while others have to travel to the lymph nodes to fully mature.

So while I don't want to say sexism wasn't a cause (though it certainly could've been), it's also possible that they just happens to find the conditions for bone marrow --> sperm before they found the conditions for bone marrow --> egg, or the conditions for sperm are easier/cheaper to produce than the theoretical conditions for eggs.
neotoma From: neotoma Date: April 19th, 2007 10:57 pm (UTC) (Link)
I'd have to read the actually paper instead of media reports, but at a guess I'd say making sperm is easier -- oogenesis requires a pretty specific sequence of horomone exposure, and throws off three polar bodies.
tdu000 From: tdu000 Date: April 19th, 2007 11:03 pm (UTC) (Link)
I would guess, and this is a big guess, although I do have degrees and a work backgound in pathology, that sperm is easier to store and easier to check on it's viability after manufacture and storage. For instance you can see that a sperm cell is dead, in some cases, just by looking at it under a microscope (I used to do sperm viability checks). I doubt you can do this with eggs (I've never worked on egg viability so that's why I'm guessing a bit).
From: (Anonymous) Date: April 20th, 2007 12:53 am (UTC) (Link)
Well, I remember when it was in the news a few years ago that they had done the first successful freezing of egg cells, ages after they'd done it for sperm cells.

For what it's worth, by the way, it isn't that women "run out" of egg cells. It's true we have a set number, but it's several thousand above anything we're likely to get around using in this life. Say a woman ovulates monthly for forty years between puberty and menopause. That's 480 egg cells she's likely used up out of, what, 200,000?

The main problems are menopause (cessation of ovulation) and age of the egg cells.

As for birth defects, they say just about everyone is carrying a couple genes you wouldn't want in a homozygous configuration.

st_aurafina From: st_aurafina Date: April 20th, 2007 01:26 am (UTC) (Link)
Maybe it's because eggs were designed for long-term storage, and sperm isn't? We come with all our eggs formed - we've actually stopped snythesizing them before we're born. Then they sit there till they're needed. Sperm are made fresh each time. Hmm. There's a big size differential - eggs are much, much bigger than sperm. On the other hand, sperm come with lots of specialised equipment like flagella. Not an answer really, just some musing.
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