According to Susskind, he says that most cosmologists do believe that the causes of our universe probably go back into infinity, therefore there is not likely to be an "uncaused cause" of the BB. Also, because of what we know about q.m., it opens the door to there being more likely a multiverse that we're part of. And also some cosmologists have hypothesized that we may be involved within parallel universes, but that's hardly a slam dunk.
Needless to say, and I hope you can get this from my posts, I'm not exactly a supporter of "uncaused causes", and this would also apply to the BB as well.
Also, string theory may well explain why q.m. is what it is, but neither is that a slam dunk.