Do you have Neighborhood Stories turned on for the households where the toddlers appeared or the couple that had the 6 babies? If you have it on, check the settings in Manage Households. If you want to stop adding the unrelated toddlers, turn off Adopt a Child. For babies, turn off Have a Baby. If you have Cats and Dogs, turn off Adopt a Cats and Dogs. If you have Horse Ranch, turn off Rescue Horses. Shutting all those settings will stop your game from giving sims and animals to you households. You can set the options globally for all your households either globally or for each household. You will need to do it separately for households in My Households and Other Households.
Hope this helps.
