No. Science is never white or black. It's various shades of grey. But the truth is always closer to one end than to the other.
In science, we try to go by consensus. You never make hay with one single study; you take a look at all of the studies and you see what the consensus, the opinion, is. You come up with a decision that, at the time, seems the most appropriate. It may be that it has to be changed in the future, because science is a process. It never really comes to an end.