I agree, and we're starting to get heavily in to epistemology here, but modern sciences do not have the ability to construct properly controlled studies, and "harder" sciences do not have enough understanding of the underlying biology to provide a definitive answer.

At best we can get a "we think it's like this", but I'm not sure I give that a higher epistemic status than tens of thousands of years of human history. This is probably a pointless discussion, since there is not enough information to reach a conclusion.