Usually, my sims give birth to 2 to 3 children, only the heir, his/her/their partners and children are going to live with parents after graduated. For the rest, I will transfer them some amount of Simoleons and let them to find a living place.
Although "For Rent" has lots of bugs, it is a good DLC because I want more living places!
(P.S. I have >700 sims in my save)
The Vatore siblings in my save maybe exceptional.
Lilith married, her husband moved in. They have 2 children in their first part of life.
Caleb married, his wife moved in. They have 2 children.
The full house 8 people were living together, until the 4 children attended college.
After Lilith's second child attended college, Lilith gave birth to her 3rd child, a girl. When this little girl turned toddler, Lilith adopted 7 more orphans and 2 kittens.
At the same time, Caleb and his wife moved to Henford-on-Bagley. Their son moved in after graduated, but he is still single.
