I was in a discussion with someone on twitter recently and the topic of fine-tuning came up. He argued that both the earth and the universe were fine-tuned for humans. I want to discuss the earth first because it is an easier argument, so it seems natural to start there.
There are many things about the earth that are just right for humanity to survive here. We are the right distance from the sun, there is the right amount of water on the planet, there's even jupiter in the solar system which seems to help reduce the number of asteroid impacts that we have to deal with. I'm sure there are many other things about our planet that are set up just perfect for life. This is interesting and cool, but does it point to God?
Let's suppose that we have this laundry list of conditions that have to be just right for life to exist on our planet. Let's also suppose that the odds of any given star randomly ending up with all of these conditions is about 1 in a billion (I have no idea how we could determine odds like this, but the real point is just that it is incredibly unlikely). If there are also a billion stars out there, maybe the fact that this 1 in a billion coincidence happened somewhere isn't quite so amazing anymore.
So how many stars are really out there? According to wikipedia, our galaxy has somewhere between 200-400 billion stars. But that is just one galaxy out of many, if you go to http://hubblesite.org, you can see many pictures like the one below which shows a huge number of galaxies, each with a huge number of stars within.
If each star represents a chance for intelligent life to evolve, the fact that it happened somewhere is actually not terribly remarkable. And wherever it happens is the only place where those intelligent beings are going to be able to look at their surroundings and say "wow, it's amazing that all of these unlikely things have happened here that allow us to exist!" But if they only consider their own solar system, if they don't consider the trillions of other stars that (as far as they know) don't have intelligent life, then they are really cherry picking the data.