Hello! So I saw challenges like this before and I just wanted to give it my own personal twist
So the whole challenge is to have 100 kids, each with a different Father (unless you have twins or triplets).
The Sims 3 base game
Have 100 kids
To start, create a female sim--any you want. (Neat, Artistic, Flirty, Family Oriented, Nurturing if you have Generations, Friendly, ect. are good traits) Give this lady sim a house and then have her meet random guys and try to hook up with them. I recommend making them a boyfriend first before you have a kid because if you don't you will have a bad rep and people will start to hate you
-Your founder may NOT have a job. This is where the artistic trait and teens with jobs come in handy.
-Your teens may have jobs but only part time jobs. No one on your lot that is older than a teen can have a job.
-Toddlers can be aged up as soon as they can walk, talk, and are potty trained. Babies can be aged up ASAP if you like.
-Children and teens can be aged up as soon as they make honor roll in school if you wish.
-If you want to make it even more difficult, forbid yourself from hiring babysitters or butlers or anyone to help with kids.
-You can't use apples/watermelon to determine the gender of the baby.
-You can't choose any traits except for the founder.
-Your founder can't get married while living in the house.
-You can move any adult out at any time but not the kids.
-The only way to really fail the challenge is if you don't get a girl.
-Fertility treatment is a good thing, as are clone vouchers if you have generations.
-No reusing a baby daddy.
-No sending kids to boarding schools.
-Although typically the youngest girl is used to carry on the game, you can use whichever girl you wish