Humans are in space. An alien race comes upon them. The aliens are single-celled, single-sexed creatures who can change their shapes and imitate other lifeforms including humans. They imitate them so well, humans do not suspect the aliens are among them. The aliens have three stages they go to in their life. Seedlings are the children and are produced by Houses. Houses produce seedlings as genetic experiments. The seedlings are taught and watched over by Tutors, what Houses turn into when they are tired of producing seedlings and want to do something else with their lives.
To the aliens, the universe is a giant mathematical equation that the Tutors created. When the current equation reaches its end, only the Tutors will survive to go onto the next equation. Everyone else will die.
The series starts with the description of one of the aliens called a child. That is considered an unusual title because it means the seedling was produced for a specific purpose. Early in the book/series, this child crashes a ship into a planet inhabited by humans (not Earth) and causes a chain of events that will lead to the child being locked in a safe in a bank while the child's House decides what to do with it.
One of the most horrific scenes that I remember was a description of the egg factory (a.k.a. The Happiest Place In The Universe). It was right up there with the last chapter of Robin Cook's Coma (SPOILER ALERT:
where the women had all their skin removed and were hooked up to this computer as part of a medical experiment)
and it goes into a lot more detail than I am doing here.
This was a lot worse in ways and not just because it involved something like a thousand healthy women. They all had their arms and legs cut off just before the hip and shoulder. They had their eyes sewn shut, effectively blinding them and their eardrums pierced so they were deaf. Either the aliens lobotomized them or others did it for them. They had their ovaries wrapped up to prevent their own eggs from leaving the ovaries while allowing the ovaries to continue producing needed hormones. These women became nothing more than living incubators completely dependent of the aliens for everything. The aliens were making babies of specific types of humans that they wanted to see continued. And the kicker was that these babies were of the human stock that made the seedlings happiest. So when these babies grew up, the seedlings would have more of the type they wanted to play with.
Now supposedly to make everything all right, the aliens were using mainly criminals who had either been given life sentences or had been deemed irredeemable in some court. But those women would be stuck giving birth for 50-200 years before being killed because their bodies could not take being used that way no longer. Perhaps the craziest thing about it was that there was at least one alien who preferred taking care of those bodies to dealing with real humans and a lot of that stuff about the egg factory was taken from that alien's POV.
All I want to know is I didn't dream it up and where I can find the book it's from. Because everyone around me keeps drawing up blanks.
EDIT: Forgot to explain that the reason the place is called the egg factory by the aliens instead of a human farm or something else is because the place where the women are human incubators is located under a giant industrial chicken farm with tens of thousands of chickens laying over a million eggs a day. Those eggs are shipped out to other planets that need them and it is on those same ships that the women are brought to the planet.