You also have to think that babies when not potty trained are in diapers, but dogs are not. There’s also dander, hair, and other allergens from pets that you don’t have to worry about with a child. Allergens from pets require quite a bit to remove, like washing walls and painting, removing or at the very least professionally washing carpet, cleaning air ducts, deep cleaning every nook for the hair, etc. This limits your pick for future renters as well, since it can be VERY difficult to remove all allergens after an animal has lived there. Kids may cause a hole or two or color on the wall, but ultimately those are a lot less time consuming and cheaper to fix.