In comments, Rob Singleton alludes to the Fine Tuning argument. (I think he alludes to it; his comment is incoherent.)
The Fine Tuning argument argues that the probability of a life-friendly universe is so unlikely that it must have been created intentionally.
There are a lot of problems with the Fine Tuning argument, though.
First of all, the Fine Tuning argument absolutely cannot distinguish between naturalism and supernaturalism regardless of how we evaluate the probabilities. The Weak Anthropic Principle states that because we exist (and we know we exist a priori), if naturalism were true we must observe a universe in which we can exist. I'll write more on this later, since it gets into complicated issues of evidentiary epistemology.
A life-friendly universe is not necessarily highly improbable. Rob mentions the "100-plus constants (that have to be there for life on planet earth)", but there are only 26 dimensionless parameterized constants in the Standard Model of physics (precision and factual accuracy do not seem to be Rob's strong suits), and many of them "describe the properties of the unstable strange, charmed, bottom and top quarks and mu and tau leptons which seem to play little part in the universe or the structure of matter." [Wikipedia]
We not certain, however, that this universe is improbable at all. We do know that the Standard Model of physics is incomplete: physicists have not yet reconciled quantum mechanics with general relativity. If they can reconcile the two, we might change our estimate of the probabilities; if we cannot reconcile the two, the universe would be a weirder place than even quantum mechanics suggests, and it's difficult to see how one would talk about probability at all. And, who knows, we might discover for deep reasons that have nothing to do with life that this is the only universe that could possibly exist.
There's also the Strong Anthropic Principle: It may be we ourselves who have brought the universe into existence, and we have evidence from quantum mechanics that atemporal causality is not impossible and cannot be ruled out on the basis of the present evidence.
For the Fine Tuning argument to have any force, it must be meaningful in some sense, at least in the abstract, to make counter-factually definite statements about how the universe might have been, but isn't actually. Some philosophers would assert that meaningful counter-factual definiteness entails an ontological commitment to the actual existence of the counter-factual conditions: in other words, for us to talk about how the universe might have been, those alternatives must actually exist. In which case, the Fine Tuning argument loses all force. If all physically possible universes exist, then of course we find ourselves in one of the universes that is physically life-friendly.
(It's notable that the strongest ontological interpretation of quantum mechanics (not counting the explicitly anti-ontological Copenhagen interpretation) besides the Transactional interpretation is the Many Worlds interpretation, which would obviously justify naturalism on the Weak Anthropic Principle.)
The above arguments are entirely speculative; I mention them for the sake of completeness.
More importantly, if we can talk in any meaningful sense about how the universe might have been, it is possible to talk in the same sense about how any hypothetical creator might have been. For each sort of alternative universe that is plausible enough to be counted in the domain, it must be equally plausible to talk about a creator of that universe. So the domain of plausible creators must be at least as large as the domain of possible universes, and therefore the probability that a specific creator exists to create a specific universe is at least as small as the probability that this universe exists by chance. Positing a creator (at best) just moves the improbability around; it doesn't eliminate it. At worst, we must count creators who might have created a universe but create no universes at all, making a creator of this universe less probable than this universe existing by chance.
Probably the most important conclusion we can draw is that even if the universe were intentionally created, we can discern nothing about that creator that we cannot discern of the physical universe. We cannot say anything about this supposed creator other than it is the sort of creator who would create this particular universe in all its details.
We cannot determine if this being wants to be worshipped or ignored. We can't tell if it is friendly, hostile or completely indifferent to human, or even terrestrial life. Just believing that such a creator exists gives us absolutely no additional justification for believing that any religious scripture is inspired by this creator. (Indeed the idea that a being capable of creating such a vast universe, of actually creating physics itself, would choose to communicate with its creation by the agency of schizophrenic prophets and parasitic priests in some a remote corner of the ancient world seems vastly less plausible than that all religions are entirely human social constructs.)
We cannot even determine that the existence of life itself was a goal of this creator or a side-effect. Indeed, the relative insignificance of terrestrial life argues for the side-effect interpretation. The mold in the grout in my bathtub is more "significant" by many orders of magnitude to all of human civilization than is terrestrial life to the ~9.2x1021 light-year3 observable universe: that specific patch of mold has more justification for believing that all of human civilization has been created specifically and intentionally for its benefit than we have for believing that the entire observable universe has been created for the benefit of all terrestrial life.
In short, the Fine Tuning argument is speculative, probabilistically meaningless, and, even if true, doesn't establish anything interesting. I think it's safe to say that, after Pascal's Wager, it's the second worst apologetic ever.