So, re-reading this:

After which, you will be required to select from the Matrix 23 individuals - 16 female, 7 male - to rebuild Zion.

It got me thinking - why exactly this ratio (and why exactly on that scale)?

Is it based on some out-of-universe scientific research for optimal seed population? Was there some in-universe explanation for the peculiar non-1-to-1 ratio?

I am fine with out-of-universe answers, but would prefer those backed by specific data (or in-universe answers based on canon material, or words from franchise workers), as opposed to pure unfounded guesses.

  • 4
    The peculiar non-1-to-1 ratio is... 2-to-1. Feb 25, 2013 at 6:52
  • 3
    @ThomBrannan - ~2.3:1 :) Feb 25, 2013 at 7:05
  • 41
    @DVK: Neo's male, isn't he? 16 females, Neo and 7 other males is 2 to 1. Feb 25, 2013 at 7:34
  • 10
    Paging Dr. Strangelove.... Feb 25, 2013 at 13:27
  • 4
    Oh, its a movie about the dangers of nuclear proliferation. At the end, when it becomes clear that war is imminent, the eponymous doctor suggests that the human race be continued under ground, with only the most fit being chosen. He mentions that it would require a 10:1 ratio of women to men, and that "the women will have to be selected for their sexual characteristics, which will have to be of a highly stimulating nature." This is, of course, a comedy. Feb 25, 2013 at 15:21

5 Answers 5


This wouldn't work for an actual population of humans. First, there is a concept in population biology called Minimum Viable Population Size. You typically need hundreds of organisms to survive. In a sheltered environment like Zion, the number could probably be reduced, but reducing it to 23 individuals (one per chromosome?!) would be a really bad idea because of how drastically it would curtail genetic diversity.

For example, the Major Histocompatibility Locus is a crucial protein involved in immune response. There are thousands of variants:

The most diverse loci, namely HLA-A, HLA-B, and HLA-DRB1, have roughly 1000, 1600, and 870 known alleles, respectively.

With only 23 individuals, the maximum number of variants (alleles) is 46--two per individual. The vast majority of our diversity would be lost, and we would consequently become hyper-vulnerable to various pathogens.

So I don't know what the in-universe explanation might be, but if it was supposed to be an out-of-universe explanation, it's wrong.

  • 8
    Zion only survives for ~100 years, so genetic diversity might not be as impotant? Feb 25, 2013 at 12:14
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    If it really was a big problem, couldn't they just free a few people from the matrix? The population of Zion isn't the entire human race after all.
    – Zoredache
    Feb 27, 2013 at 8:54
  • 3
    they are 24 individuals, not 23. it's a trick to your cognitive bias. See Thom Brannan's.
    – n611x007
    Jun 10, 2013 at 4:52
  • 10
    I suspect you are over-thinking it. Who cares about genetic diversity? Not only do they only need to last for a few generations, but they will end up freeing thousands of other individuals. Starting with 24 is irrelevant. May 6, 2014 at 20:52
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    This answer ignores the fact that the new Zion would then proceed to free additional people from the Matrix.
    – Ellesedil
    Apr 20, 2016 at 18:24

I think you are forgetting, that Zion survives not only by generations of people, who are free of the matrix, but also by those that are freed from it.

Average spaceship crew in the Matrix consisted of 8 people. This might mean that 23 means the number of people needed to operate two ships and get some more people out of the matrix to get the civilization really going, with the rest operating controls in the city.

Theory may also be calculated by the machines giving the minimum number of individuals needed to operate a society (minimum being the chosen amount to prolong the people numbers growth to delay the next war). The decision might also be based by previous experiences, since this being not the first time the machines claim to have done this.

  • I haven't forgotten about extraction, but I definitely didn't consider that the 23 could have been due to "ship+city" initial specialization. +1 Feb 25, 2013 at 14:37
  • 3
    they are still 24 individuals. you have been tricked... a in a collaboration between your cognitive bias and the Architect! it does good for 3-12 initial ships.
    – n611x007
    Jun 10, 2013 at 4:56
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    @naxa - Who is the 24th? The One is not part of the initial cohort.
    – Rex Kerr
    May 6, 2014 at 22:57
  • @RexKerr The (previous) One is described as freeing the first of Zion's inhabitants and teaching them. The One would have to be part of the initial cohort in some way.
    – OrangeDog
    Oct 17, 2019 at 15:04

The Matrix makes tons of references to Religion. Genesis 7:16

Those that entered, male and female of all flesh, entered as God had commanded him; and the LORD closed it behind him

Maybe it has nothing to do with genetics like we would like it to be?

  • 7
    I was about to downvote this, then I got the connection. Could you explicitly mention the use of the numbers to get 7:16?
    – Bobson
    May 21, 2014 at 17:54
  • 6
    Why Genesis 7:16 and not Leviticus 7:16 ("'If, however, their offering is the result of a vow or is a freewill offering, the sacrifice shall be eaten on the day) or Numbers 7:16 ("One kid of the goats for a sin offering") or any of the other books of the Bible?
    – Valorum
    Apr 14, 2017 at 14:31
  • "You are altogether beautiful, my darling; there is no flaw in you", "And if I do what I do not want to do, I agree that the law is good."
    – OrangeDog
    Oct 17, 2019 at 15:12

Since no one answered why 7 males and 16 females yet, I'll leave here my guess.

The 23 freed humans would need guidance of some sort, when fresh out of the Matrix, much like Neo needed. It is likely the One would go with them to rebuild Zion, and provide some guidance in this new world.

If you add the One gender (male in the case we witness) to the numbers, that leaves 8 males for 16 females, leaving two females for each male. This could ease repopulation, accounting for pregnancy downtime of each female. That sounds exactly like the thinking of a machine to me.

I'll add to that, that genetic diversity is completely irrelevant. There would still be plenty of diversity if you take into account the people connected to the Matrix - whom the zionists could free and procreate with.


7:16, men:women. Each man could impregnate each woman once, resulting in 7*16 children over the course of at most a decade (Since pregnancy takes 40 weeks plus recuperation, and each woman would get pregnant seven times).

Now, you have 112 children, gender not yet known. This is where math gets a little out of hand. You now need to calculate how many potential mates each of these children will have.

Assuming we ignore gender here, every child has 15 half-siblings by their father (one man and 16 women), and 6 by their mother. That means each kid has an unlikely maximum of 91 potential mates, and a more likely 45-ish.

After that, the math gets really nutty and I lose my mind, however, you could probably still have a rather steady population rise if you avoided screwing your half-siblings...

  • 1
    You are, of course completely forgetting that these individuals can get additional humans out of the Matrix, obviating the need for incest.
    – Valorum
    Apr 20, 2016 at 16:30
  • Well yeah, I know they can get more Red Pills to solve this issue a little faster. And that's just it, this plan is entirely avoiding incest, by utilizing the maximum available non-related mates. That comment was more like an explanation of how to prevent a genetic meltdown if they couldn't get anybody else. Apr 20, 2016 at 16:44
  • 1
    You're also completely neglecting the fact that their primary focus (at least for the first couple of years) will be survival, not breeding.
    – Valorum
    Apr 20, 2016 at 16:45
  • Breeding is still a part of survival, the people of Zion definitely play the generations-long game. It simply seemed that the question was as to how 7:16 made any sense, and I admit that it doesn't. There's no need to be harsh, I just misunderstood the question, my comment still made sense Apr 20, 2016 at 16:48
  • Oh, there's definitely a breeding angle here (or why bother getting a mix of men/women out), I'm just saying that it's not their immediate priority, nor do we especially need to look at more than the first generation in terms of interbreeding.
    – Valorum
    Apr 20, 2016 at 17:13

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