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I am working on a setting in which there are a very limited number of human females remaining, and the intent is to repopulate as quickly as possible. Given a modern level of medical technology, what is the maximum number of viable eggs that could be produced by one woman assuming she is somewhere around 25 years of age and reproductively healthy?

EDIT: Just realised I should clarify, in this setting there are artificial wombs available, so it is not a matter of how many pregnancies are possible, just how many eggs could be produced per woman for the purposes of in vitro fertilisation.

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    $\begingroup$ @RonJohn No, it isn't. If you read the question, you will notice that I have stated "given a modern level of medical technology". Thus far, no one has provided evidence that harvesting whole ovaries can be done given modern technology. $\endgroup$
    – Arkenstein XII
    Commented Nov 7, 2018 at 21:12
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    $\begingroup$ #1 We've been harvesting human eggs, freezing and then thawing them to viability for decades. #2 "a modern level of medical technology" and "there are artificial wombs available" are inconsistent, since artificial wombs for humans are not available. $\endgroup$
    – RonJohn
    Commented Nov 7, 2018 at 21:23
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    $\begingroup$ #1 Have we been doing that by harvesting all the eggs at once? #2 Artificial wombs are not involved in the procedure of extraction. The question makes it clear that I want to know about using a modern level of medical technology in regards to extraction, regardless of what technology will subsequently be used to grow the embryos. #3 The title is not the question. The question is very clear that I am looking for a realistic answer to a hypothetical situation. I am not intending to actually do this. $\endgroup$
    – Arkenstein XII
    Commented Nov 7, 2018 at 21:30
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    $\begingroup$ @RonJohn Even if it seems obvious to you (and indeed it was my very first thought as well), that does not mean it is obvious to OP, so you are essentially saying that OP is either asking a question they already know the answer to or are ignorant. $\endgroup$
    – Loduwijk
    Commented Nov 7, 2018 at 21:49
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    $\begingroup$ For your research, focus not on women undergoing fertility treatments but on women who donate (or sell) their eggs. Not all women using fertility treatments to increase egg production will have their eggs harvested for IVF or the like. So in those cases, you don't want maximum egg production. Also, women undergoing fertility treatments are more likely to be older and they will usually have diagnosed fertility issues. So, even with the same treatments, their egg production might be lower than that of a young healthy woman donating her eggs. $\endgroup$
    – Cyn
    Commented Nov 7, 2018 at 22:24

6 Answers 6

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260,000 embryos
Remember, women are born with all the eggs they are ever going to have, and they don't make any new eggs during their lifetime. Women are born with approximately two million eggs in their ovaries, but about eleven thousand of them die every month prior to puberty.

If you were to extract all those eggs at a young age, and had some kind of artificial womb to grow the babies, then you could have a lot of babies.

Now, if you waited till she was 25 to harvest the eggs, then it's going to be a lot less.

11,000 a month till age 12 = 1,584,000.
Then 1000 a month from 12 to 25 = 156,000.
So you are looking at around 260,000, give or take a few.

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    $\begingroup$ I think you should edit the numbers in this answer. Looking at your own linked article the diagram for example shows a logarithmic scale that is already between 200.000 and 500.000 by the time they hit 18. The article lists this: "To recap, the average woman will have three hundred thousand to four hundred thousand eggs at the time of puberty.". The article then mentions that from puberty you lose 1000 eggs per month. $\endgroup$
    – Demigan
    Commented Nov 7, 2018 at 21:05
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    $\begingroup$ @Demigan they don't really specify what age puberty is i the article. I have heard that it is happening younger, but it's still a case by case basis. That being said, I missed the bit about 1000 eggs lost a month. so I can update that number. $\endgroup$
    – AndyD273
    Commented Nov 7, 2018 at 21:19
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    $\begingroup$ While this was my first reaction as well when reading the question, another issue needs to be addressed, to which I do not know the answer: are they all ready and available for this at all times? When a doctor removes eggs for this purpose, can they just choose any at all, or is there some concept of egg maturity that needs to be taken into account? I assume that all could be taken and used, but I'm not sure. $\endgroup$
    – Loduwijk
    Commented Nov 7, 2018 at 21:55
  • $\begingroup$ That's not the best ref, being a sales page and thus written by salesmen not scientists. That the salesman works for a scienc-ey sort of business, does not oblige him/her to get the facts right. $\endgroup$
    – Harper - Reinstate Monica
    Commented Nov 8, 2018 at 15:22
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Recent research has suggested that the conventional wisdom is wrong and that people can generate new eggs within their bodies that were not in there when they were born.

On the other hand, some other smart people have looked at the research and the evidence and remain quite dubious.

On the gripping hand, I don't see any data on the rate of egg creation, which is sort of what your specific question requires, so you're still kind of on your own.

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  • $\begingroup$ gripping hand! nice, Heechee dude. $\endgroup$
    – Willk
    Commented Nov 7, 2018 at 21:08
  • $\begingroup$ @Roger You're not wrong. The research I have done seems to indicate that the total number of eggs a woman has and whether new ones are produced are not relevant. Whatever the answers to those questions may be, the maximum number that can be medically extracted safely and given modern technology is going to be much lower than that. However, what that number would be given these technological and biological limitations continues to elude me. $\endgroup$
    – Arkenstein XII
    Commented Nov 7, 2018 at 21:09
  • $\begingroup$ The provenance of this link is much better. Guardian being a newspaper, of course they are out to sell prescriptions but they have no angle to lie, in fact innacuracies hurt their reputation. $\endgroup$
    – Harper - Reinstate Monica
    Commented Nov 8, 2018 at 15:27
  • $\begingroup$ @Willk That's a proper old school sci-fi reference right there :) $\endgroup$
    – Tim B
    Commented Nov 8, 2018 at 16:02
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While I don't have actual numbers for you, the method will be to induce maturation of multiple eggs in a given ovulation cycle, then harvest them. Harvesting whole ovaries doesn't work. The eggs have to ripen. We don't know how to do that.

Not all women will be able to produce eggs at all, others will react badly to the medications and surgeries, and number of eggs as well as endurance in number or frequency of harvesting cycles will vary woman to woman too.

For the purpose of obtaining a decent average, you need the following information:
Number of usable eggs obtained X number of harvesting cycles in any given time period

Don't assume one cycle per month. It may take longer to get things going hormonally. And bodies need to rest. The few citizens of your world who are able to provide eggs aren't resources to exploit. Don't assume that if it's safe to do a harvesting cycle, say, every 3 months, that this means 4 times a year times the number of years the woman remains at peak fertility. It doesn't work like that. There may be a maximum number of cycles someone can endure.

A lot of people are saying things like, well at least you can get one egg per month. But you can't. Remember, the eggs don't just come out like a chicken's. You want a viable human egg, you have to perform surgery. Don't need a lot of cutting, but it's still invasive. You really want to do that every month?

For your research, focus not on women undergoing fertility treatments but on women who donate (or sell) their eggs. Not all women using fertility treatments to increase egg production will have their eggs harvested for IVF or the like. So in those cases, you don't want maximum egg production. Also, women undergoing fertility treatments are more likely to be older and they will usually have diagnosed fertility issues. So, even with the same treatments, their egg production might be lower than that of a young healthy woman donating her eggs.

I found this site that describes the process (and side effects... Yikes! Tons!). Perhaps you can call them and saying you're researching for a novel (or whatever it is) and would they mind telling you the range and average number of eggs harvested, how long between harvests, and how many times someone can safely donate. http://web.stanford.edu/class/siw198q/websites/eggdonor/home.html

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  • $\begingroup$ On that site the operative word is "relatively" unregulated. It's still medical, which means the universe of standard, "not particular to fertility" medical rules does apply to it, from "do no harm" to sterile fields to HIPAA. $\endgroup$
    – Harper - Reinstate Monica
    Commented Nov 8, 2018 at 15:32
  • $\begingroup$ For sure. But that doesn't mean women undergoing the procedures won't have issues. A large number do. Just the hormones alone! The only "fertility" drug I ever took was progesterone (the bio-identical form of a basic hormone my body didn't produce quite enough of). It gave me liver damage. These are not benign medical procedures, even when done perfectly to all sane medical standards. $\endgroup$
    – Cyn
    Commented Nov 8, 2018 at 18:16
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https://www.rogelcancercenter.org/fertility-preservation/for-female-patients/normal-ovarian-function

You start with about 1 million eggs at birth but these decline per month. At puberty you have about 300.000 eggs left. In the 30 to 40 years after puberty these are also depleted. This means at a "worst case" you lose about 10.000 eggs per year, assuming puberty for women starts around 12 years (again keeping it low for a worst case scenario) you would have 170.000 eggs remaining.

So given enough artificial wombs, you harvest the entire ovaries and use techniques to have a 100% success rate if maturing and infecti... I mean fertilising the eggs with male DNA, you would have a pretty awesome growth.

Edit: Willk in the comments noted this source: fertstert.org/article/S0015-0282(17)32178-7/fulltext. Which mentions a current-day method of harvesting eggs. Such a method, if not a more advanced due to the technology seemingly available, could be used for the harvesting.

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    $\begingroup$ This assumes that the woman in question is willing to have her ovaries removed, which seems like it'd have health consequences for her? Also, is harvesting eggs from whole ovaries even possible given modern technology? $\endgroup$
    – Arkenstein XII
    Commented Nov 7, 2018 at 20:29
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    $\begingroup$ @ArkensteinXII There's a limited number of females remaining, artificial wombs are available with apparently no limit to them as the question is about the amount of eggs available and harvesting is apparently possible as well. So I would guess that the women have little question in willingness, and considering the technology they could leave a portion of the ovaries or perhaps use a technique where they keep the Ovaries inside the womb but extract most of the eggs in several operation sessions (likely through endoscopic operations through the uterus, no sense cutting them open). $\endgroup$
    – Demigan
    Commented Nov 7, 2018 at 20:56
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    $\begingroup$ With current tech it is possible to harvest wedges of ovary, freeze them away, and later get out eggs and make babies with them. fertstert.org/article/S0015-0282(17)32178-7/fulltext $\endgroup$
    – Willk
    Commented Nov 7, 2018 at 21:08
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    $\begingroup$ @RonJohn I could change the answer but I don't think there's much point. The question is about the amount of eggs available, the answer lists the amount available. If the OP wants to give the women some choice in the matter that's his call and I think his choice on how much freedom those women get in his story. $\endgroup$
    – Demigan
    Commented Nov 7, 2018 at 21:18
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    $\begingroup$ This is a good answer; don't change it. I was just emphasizing that willingness has nothing to do with it. $\endgroup$
    – RonJohn
    Commented Nov 7, 2018 at 21:20
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Assuming a woman is fertile from age 13 to age 48, producing one egg per month, she can produce about $12 \cdot 35 = 420$ eggs.

If you take her from age 25, this means about 276 eggs.

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    $\begingroup$ My understanding is that there are modern IVF techniques that can induce the release of many more eggs, however I can't find any information on how many, or whether the technique can be done repeatedly. Hoping someone might know! $\endgroup$
    – Arkenstein XII
    Commented Nov 7, 2018 at 20:13
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    $\begingroup$ @ArkensteinXII, if I recall correctly more than 10 in a single shot of hormonal stimulation is dangerous for the woman health $\endgroup$
    – L.Dutch ♦
    Commented Nov 7, 2018 at 20:16
  • $\begingroup$ That's good to know. Thanks! Any idea whether the hormonal stimulation has a limit on how many times it can be repeated? $\endgroup$
    – Arkenstein XII
    Commented Nov 7, 2018 at 20:31
  • $\begingroup$ They normally look to harvest 5 or 6 eggs per round. However, as discussed in other answers this is not an upper limit on obtaining eggs. $\endgroup$
    – Jack Aidley
    Commented Nov 8, 2018 at 15:46
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I wasn't sure if you could just take them all at once, but someone said in comment elsewhere that you cannot. I leave the route where you can below in case OP wants to go that way, especially since there is some advanced technology. But going the route where you cannot...

For each woman who wants to contribute to this, I will assume the slowest normal production of approximately 1 per month. In 10 years, that should lead to greater than 100 children. Approximately half of them are themselves female, and at approximately that time those new females can contribute as well. For each one of them who does, the same pattern continues.

So worst case scenario is that every decade the population multiplies by approximately 100. In 2 decades, that is a factor of 10000, 3 decades is 1 million, 4 decades is 100 million, 5 decades is 10 billion which is more than are on Earth today. And there will be no problem whatsoever with fertilization from males at this rate of population growth.

So a planet can be completely repopulated, at least by the numbers, in 1 person's lifetime.

But remember, that is from 1 starting woman who wants to contribute. For 100 starting, subtract 1 decade from the repopulation. Further, some people suggest that you should have tens of thousands of people minimum for a repopulation due to genetic diversity, so if you have that then subtract 2 decades. The planet has plenty of population in 2 decades, is fully repopulated (to today's level) in 3 decades. In 4+ decades it has a huge number.

Previous Answer (the fast track to full repopulation in 2 years)

My initial reaction was the same as in Andy's answer (though I did comment there about how I was not sure if you could just take them all at any time), but since your purpose is planetary repopulation you can go a step further.

  1. That is per woman, but only the women who contribute. Some might not.

  2. That is just the first generation of repopulation...

So you do your first generation of repopulation, and you have approximately (number_of_women * 100000) new people now, but approximately half of them will be female as well, so if this is the route you are going, in just 1 year you can do this again with females which possess even more eggs, on the order of a million.

I will assume for a moment that "a very limited number of human females remaining" is 10. Let us ignore genetic diversity for a moment, as this calculation is just to make a statement about population growth rate. So we have 10 females.

10 * 100000 = 1 million babies next year

Then you collect the eggs from the new females, approximately 500000 females at approximately 1 million eggs each...

500000 * 1 million = 500 billion new babies that year

So in only 2 years you have gone from a few humans to 500 billion; that is already 100 times more people than are on our planet today. And if you did the same thing again the next year, there would be... what's after a trillion again? Whatever, a huge number of people.

However!...

Those eggs need to be fertilized, so now you have to ask the same kind of question about males. They generate a lot of sperm all the time, and each 1 could fertilize a very lot of eggs, but not a million of them all at once. So you would need to fertilize them in large batches which would slow this all down a bit. However, this slower rate is still exponential crazy-super-high rate of population growth, and once again total repopulation would not take long at all.

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    $\begingroup$ Even if you can take the whole ovary, there are some problems whose solutions are not mentioned here. Making the babies is one thing. Keeping them alive is another. 10 women and a presumably similar number of males are certainly not going to be able to care for 1,000,000 newborn babies, let alone 500,000,000,000 of them. The limitation here won't be the ability to get and fertilize eggs, but rather having a sufficient number of people to care for the children until adulthood. $\endgroup$
    – reirab
    Commented Nov 8, 2018 at 3:43
  • $\begingroup$ @reirab I agree completely, but OP says there are technological aids, such as the artificial wombs. How to care for all of them is a matter I will leave up to them. Maybe they have nanny bots (something we partially have even now; television is used by some to stunning [not necessarily optimal] effect). Artificial feeders would be even simpler than artificial wombs. I don't know, I was merely considering the question asked. But you are correct reirab. $\endgroup$
    – Loduwijk
    Commented Nov 8, 2018 at 14:47

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