A married couple was horrified at the world and decided to hide their children (and maybe some others) from anything outside.

Start off by creating two Sims with any traits, but these traits are recommended:
Family-Oriented, Nurturing, Neat, Technophobe, Natural Cook

The sims must be a married couple. Any gender is fine, as you can have children through adoption, kidnapping, or pregnancy. Delete the school. Now it's time to have some kids! You can either adopt or give birth to them, or "kidnap" babies/toddlers by using the "add to active household" cheat. (Type ctrl-shift-c, then type testingcheatsenabled true, then shift-click on the toddler you want to kidnap. The option should be there.) Then, build a basement under a normal-looking house. You may use money cheats. To get the adults into the basement but not let the kids out, you may either use a teleportation cheat or build a room around the staircase to the basement, and make the adults the only ones able to enter the door. Keep the kids in a perfectly safe little world. No TV, computer, or books allowed! That introduces the kids to the outside world.

You must make the traits of the kids ones of innocence and perfection. You have to teach the toddlers toddler skills and have a perfect pregnancy to do this (you may not change their traits). Since the kids/teens are unable to go to school and it will randomize the traits, to use cheats and change a randomly-generated trait, you must do certain things.
For you to be able to change a child's trait: Make them best friends with everyone on the household, and make sure they master 1 skill.
For you to be able to change a teen's trait: Make them master 2 skills.
To change a kidnapped toddler's trait: Age them up to a child with ALL toddler skills mastered, this includes xylophone and peg box.
The first child who ages up into a young adult has to have their innocence stolen. They are finally allowed upstairs, and they must marry someone and continue their parent's deeds.
Everyone else stays in their little world forever. They must become a young adult with the following traits: Good, Never Nude, Friendly, Perfectionist, and Childish.
When you have created 12 adults with these traits, you win.
If anyone except the first young adult leaves the basement, you lose. If someone ages up without the proper traits, you lose. If someone from outside who is NOT the person your first young adult chose to marry talks to your innocent kids, you lose. This includes the babysitter.

Questions, comments? Reply!

This sounds like a really cool challenge. Can't wait to try it out!

Thanks! Good feedback always makes me happy

This sounds a bit like the premise of the movie Dogtooth, actually. Parents trap their kids in the house until adulthood. I'd like it more if this challenge was equally dark as the film turns out to be, but maybe that's just me.

If the parents are authors, could their own books be kept in the kid's room(s)?

Is the first child who ages up into a young adult who has his/her innocence stolen supposed to move out or stay in the original house? Going along with that, can it be a specific amount of generations instead of having 12 children in the same house, I dont really want to use a cheat to have more than 8 sims in a household. Thanks!

sounds interesting may try this

OBJECTION!

Inocent children won't have "never nude" they are innocent enough to understand the meaning of nudity

I think you can use the Nraas Career mod to simply homeschool the children.

Yes they can have their parent's books, yes the oldest stays in the original house, and using homeschool mods is fine. I don't really use mods (mostly just CC) so I wasn't aware of a homeschooling mod.

How would we keep the children home without mods? You wouldn't want social services finding out. Should we delete the school? I really like the idea of the parents trying to forever keep their kids from finding out how bad the world really is.

You can delete the school, and Social Services in the Sims wouldn't do anything unless your children starve or get very lonely.

If the parents have logic level 6, they can increase their child's grade in school through tutoring, which would basically be homeschooling.
If I were to use this method, would the child have to stay on the honor roll until they age up for me to pick their trait? This would (hopefully) make up for overcoming the forced random trait.

If that works, then absolutely do that.

I cannot wait to try this out! This sounds awesome!

this looks fun i gota try it out