As long as "God" remains in the realm of the supernatural, ie, the unobservable, there will never be scientific proof that he/she/it exists by definition.  Science, by definition, is about building and testing hypothesis based on repeatable, observable experimentation.  Anyone who expects to find scientific proof for "God" either has a non-traditional view of "God" (ie God is not supernatural) or else has a mistaken view of science.