First of all, I want to say that I didn't intend to say biased towards a particular, singular outcome.
Now, per se the scientific method isn't Biased. The issue lies more in what actually happens in reality when scientists do science. This is how I see it mostly:
1) You observe something, a phenomenon, etc. in nature
2) An idea pops into your mind about why this is, and/or what this implies. (The idea can sometimes come by it's own though)
3) You formulate this idea in the form of a hypothesis. You make a prediction
4) You imagine a way to test this prediction, and you do it.
5a) If the outcome is positive, the hypothesis stays the same. Test something else about it (if it has multiple facets)
5b) If the outcome is negative, then you will adapt your hypothesis to the very extent that it is adaptable. Only when unreconciliable with the data will you discard it.
6) Eventually promote it to theory.
In essence, this is what happens most of the time. We can already see some bias being induced by point 5b). A scientist likes his hypothesis, it is the fruit of his mind and he will keep it alive as long as possible. This does not mean that in some cases, oher data won't come around and completely falsify it, forcing it to be discarded. But I do think that in some cases it leaves place for bias.
An additional point must be made that this method works very well. Science hs been proving time and time again to be reliable in this manner, especially in operational science. I do think, however, that when it comes to historical science, a Bias is much more easier to induce itself, particularly in point no2.
I'll have to finish this a bit later today. I hope you find everything reasonable up to this point.