What are the odds of God existing?

You are committing the logical fallacy known as The Fallacy of Composition; just because objects in the universe have causes in no way implies that the universe itself has a cause.In any cases if the universe has a beginning point, it is probably incoherant to talk about anything having caused it, or anything being before it or it coming from anything because all of these terms are inextricably linked to the concept of time, and time is itself a feature of the universe (the whole space-time thingy).The rest of your argument is pure probabilistic ignorance: the probability of an event is entirely independent of the number of possible outcomes. Just because there were two possibilities (which there aren't) does not in any way imply that they have to be equal. To illustrate this let me give an example:Throw a glass out of a second story window onto the ground below, there are two possibilities: the glass either shatters or it doesn't - which do you think is more likely?