The Principle of Contingent Causation: The Impossibility of Infinite Regress.

[Belacqua]

if anything could have been different in the universe, the universe (being the superset) could have been different, therefore the universe is contingent. You don't have to agree with this point, if you're a necessitarian or modal realist or whatever, but this is the common-sense view (whether you like it or not).

What you're talking about here isn't even a religious idea. This type of contingency doesn't address the whole universe being contingent on a single cause (which people might conclude is God), but that everything in the universe is contingent on other things, and could have been different. 

And it's not just socks, it's much smaller things than that, including observed quantum events. This is from the Wikipedia page on the "Many worlds interpretation." 

every observation can be thought of as causing the combined observer–object's wavefunction to change into a quantum superposition of two or more non-interacting branches, or split into many "worlds". Since many observation-like events have happened and are constantly happening, there are an enormous and growing number of simultaneously existing states.

...which is way over my head, science-wise, but seems to say that not only are there a hell of a lot of states of the universe, but that each of them is contingent on "observation-like events." 

So lots and lots of contingency there, and no God-talk at all.