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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. ;)
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.
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?

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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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