I live in the city too, have for the last 3 years. My 9 year old cat grew up in the country. Loved being outdoors. Once we moved to the city, things changed. Now, my three cats are only allowed outside on a leash. And they know it. How do I know they know it? When they want to go out, my cats bring me their leashes! Don't push your cats outside. Your cats are smart creatures. If they want to go outside, fine. But make sure it's on a leash so that you know they are going to be alright and not get hurt by another animal (or worse, get killed).