This is one way it could have happened.
Or God may have created the universe.
One of these notions strikes me as ludicrous.
These notions are not mutually exclusive.
Science is bound by Natural Law. I think it is ... challenging ... for science to explain how a milligram of material can be used to create trillions of tons of matter.
The fact that String Theory (apparently) explains how this can be so, goes a long way toward explaining why String Theory is not taken seriously by a lot of people (the WSJ had an article a few months ago saying that Physics may have wasted a few decades devoting much of its best talent toward a theory that has become a joke).