Yes, I do believe in other life forms and other earth-like planets, since there have already been over 400 suspected planets that have earth-like characteristics. I am very into this type of a topic. I would say that there are no creatures out there like us, no humans anywhere else. We are uniquely human. I believe in aliens, but they have not visited earth (sorry UFO enthusiasts). They may have discovered it, but have not visited it yet in our life span. If aliens were to visit us, some government corporation would hide them, inspect them, dissect them, and try to gain intelligence from them. Aliens would not attack another life form, I believe they would be much like us in thinking that visiting other life would be a way to connect and intertwine with each other to find out more about living organisms. So yeah, there is hundreds of other earth's, we just haven't discovered any with living intelligence.