The Big Bang shows that all of time, space, matter, and energy started at a single moment in the past, therefore whatever started it has to be outside of time and space. You cant posit a materialistic explanation because there is no matter there before the beginning to do the causing.
Therefore since God is transcendent and exist independently of the universe we can not apply our logic and reasoning which are limited and dictated by the laws of the universe to Him. Thus the Law of Biogenesis can not be applied to God.
