The Big Bang states that the Universe gave birth to itself, and by implication gave birth to any gods or other form of Deity that may be around today.
No, it doesn't. You might want to read up on the origins of the Big Bang theory, and the Catholic guy who invented it. It's entirely possible to believe that a being outside the space-time continuum created our universe with a bang -- or laid an egg which hatched, or farted or sneezed out the Cosmos.
I don't accept any of these theories, mind, but there's nothing directly contradictory about believing in a creator outside the continuum created in the Big Bang; indeed that's what some multiverse theories (e.g., black hole cosmology) amount to, though of course they're not speaking of a conscious creator.