Rotational Play - Keeping the population in check!

I just go by what I feel like for the particular household. In my current save, some only have two children while others have six. If I want to check on the population, I have a family tree I use; or if I don't want to leave/minimize the game, I just open the "Options" tab and select the next tab where the culling limit is listed (can't remember exactly where that's under right now).