The title alone is Ironic.
There are biases in science, but yet from my point of view,
bias as a belief itself is unscientific.

For example one scientist comes with a new theory.
But another scientist refuses to believe it because this new theory
seems unlikely. It might not be true because it is unlikely.
But because it is unlikely and therefore he chooses to believe it to be untrue, he has no reason to further investigate and research this theory.
And for that reason it will never be proven or unproven
and that brings true science and pioneering in science to a halt.

I'm pretty sure such biases have happened before with theories that turned out to be true in the end. But because of biased "scientists" that want to protect their reputation or don't want to be proven wrong, it took a very long time before one was brave enough to challenge this bias. And truly be objective about it.