It's not fine-tuned. Well, it is, but not by a creator. The fact is, we live on a planet that is just the right distance from the sun to have a temperature that we can survive in, suitable gravity to attract water and air, and many other factors crucial to our survival. But the fact that we live in such a place is not evidence of God-- we couldn't live anywhere else! The physical conditions for life were set before we evolved, so we naturally evolved to survive in the conditions we had available to us. Think about how many planets there are out there, and life has not yet been found to have evolved on any of them except this one. If there was a creator, why didn't he create life on some of those as well? Its because of the sheer improbability that life can exist-- but a God should have been able to create life on any planet, just by varying the conditions required for survival! It would be better "proof" of God if humans were found living somewhere where the conditions were impossible for us, than somewhere where they are exactly suited to us.