As crazy as it sounds, I kind of want it to happen again. Melanie had twins some time after the triplets and a single nooboo in between. But there is just rarely spots enough left in the household. If she has twins this time, then she will have had 12 kids all in all. I don't know why, but I have been having that number as a goal. Nowadays, that is a lot of children, but in earlier times it was pretty normal with no means of birth control other than holding one's horses.
@Deklitch It takes bravery to explore having multiple toddlers in The Sims 4. It's awesome that you are having good fun with it. I am too now, for some reason. Sulani is almost out of room for more of Melanie and Uku's grown up kids. Guess I could start populating Newcrest with them, but then they won't be wandering around, unless I have my family visit other places. All of the kids receive the key to mom and dad's house when they move out, so someone is always there. But I don't think that will change even if they move away from Sulani.
@Rainbow Dash I think raising several toddlers at once is probably most scary if you are pressed for time. I take it slow in my game and have aging off. Sometimes it will take days for them to completely learn something. Potty is the only thing requiring you to actively interact with the toddler. All other skills, they will slowly learn on their own if provided with objects that teach the skills. Plus, the other Sims in the household (teens and up) autonomously give flashcard lessons as well. But you already know all that