[A4A] The experiment of Vault 69

Vault 69 has always been a bit of a joke; we know very little about it, other than the nature of its experiment. Vault 69 contained 999 women, and one man. This ridiculous gender disparity, along with the number of the Vault, means that the Vault is basically just a cheap sex joke.

But what would it be like to actually try to make the Vault's experiment work? The obvious problem is that the Vault faces generational collapse, unless their sole male resident gets to work fathering as many children as possible. It sounds like a great time, and to a certain extent, it probably is, but it's not without its problems. His body would be pushed to its limit, forced to fuck as much as humanly possible every day. They possibly would even give him drugs to keep him going longer. Another issue is that he shouldn't have sex with the same woman twice, at least within the span of one month, so as not to waste the opportunity to impregnate someone who hasn't had a chance yet, which means that forming any sort of lasting relationship is difficult.

The women of the Vault would have to separate into different cohorts based on where they are in their menstrual cycle, and avoid contact with other cohorts, to avoid their cycles synchronizing. Otherwise, the entire Vault would ovulate at the same time, massively reducing the number of women who it is possible to impregnate in a given month. The Vault's single male resident would spend any given time of the month with the cohort that is most fertile, before moving on to the next.

It's frankly inevitable that the first man would probably die a premature death, either as the result of some jealous feud, or simply from his body giving out from exhaustion. And while he might have impregnated a significant fraction of the women of the Vault, it probably wouldn't have been enough. There are still hundreds of women who have not given birth, and if the next generation of Vault dwellers were the only ones left, there would be a massive population drop, and a dangerous lack of genetic diversity, since all of them would be half-siblings.

Therefore, there is only one solution: once all of the male children came of age, they would need to continue their father's work. More specifically, they would need to breed the original generation of women, specifically the ones that were not impregnated in the first generation. This would maximize the amount of genetic diversity preserved across generations, a necessity in a closed population with limited breeding stock. The women they were breeding would naturally be much older than them, and frankly desperate for a chance at motherhood. There would be a larger number of available men, but they would still be heavily outnumbered by women. Each boy would probably have a small harem of older women who were hopeful of getting bred by him.

As for the female offspring of the first generation, they would be in something of a pickle, as far as finding a mate goes. All of the available men would be needed to breed the first-generation women, and are all their half-brothers anyway. So for second-generation girls, a chance at partnership or motherhood doesn't seem to be in the cards. Their only chance at love would be with each other. So many second-generation girls would enter into lesbian relationships with each other, occasionally having scandalous but strictly non-procreative dalliances with one of their half-brothers.

But then when you reach the third generation, something interesting happens. The first generation of women would be too old to breed any more, and so the most genetically distant women from the Vault's third-generation men would be the second-generation women. So yet again, for the purpose of maintaining genetic diversity, there would need to be a generational gap in the breeding population, with younger men breeding mature women. Once again this leaves the younger generation of women without partners, forcing them to find love with each other, although at this point, the breeding population would be enough generations removed from the "patriarch" that there might be less risk in partnering up with their own generation. However, the boys of their generation would technically be their cousins, so procreation would be discouraged.

And so over time, the Vault would naturally and inevitably settle into a strange new normal, where most young men of breeding age are partnered with mature women for the purposes of procreation, while young women are forced to partner with each other until they come of "breeding age," which isn't until around 36 or older. Relationships among the same generation carry the whiff of incest, making them naughty and frowned upon, and only for fun and pleasure, not for love or procreation.

I tried to think about this as rationally as I could, but it's still pretty exciting that the options turn out to be

1. One man breeds a thousand women
2. Society naturally evolves into young men having harems of milfs while young women lez out or do incest

If we were to play this prompt out, those would be your options, by the way. We could play out the first generation, navigating the fraught but exciting prospect of one man trying his hardest to breed a thousand women, or explore one of the later generations, with their complicated new social norms.