Before continuing, what is religion? I met several atheists that state that atheism is not a religion. So, to keep the game fair, let us instead talk about world-views. A Christian bias in science could be compared to a communist bias, or a bias by a liberal atheist. So, should science be free from the impact of world-views, religious or otherwise?
For many parts of science, the matter appears not of great importance. As a computer scientist and mathematician, doing science without the danger that the outcome of my research is influenced from my religion seems easy. I thank God for what he gave me (as my job is a wonderfull one), but my algorithms and theorems can be understood and verified (or disproved if I made an error) by everyone, independent whether they are Christian, atheist, or have another religion.
Should science be carried out without impact from ones world-view? At one hand, people will often be inspired by their world-view to do what they do, e.g., doing science that may lead to improving the world by being inspired by their religion. At the other hand, there are a few cases where the outcome of science is desirable, or undesirable as there may be agreement or disagreement with ones world view. This, however, does not happen regularly, but it does. And, also, outcomes of science are often interpreted such that the interpretation fits the world-view of the interpreter.
In my own field, I see a connection of outcomes of game theory with politics. I think that these often show that many of the things said by people that want a liberal economics are incorrect, and I think that the results show that more influence by a democratic government are to the benifit of all (or all but a few of the very rich) people. But, for much of science, there are no or no clear connections with the world-views, and the big questions of life.
In some cases, there are, and these are of course, where we have the clashes, the discussions and the fights. The discussion about the origins of life, and the diversity is a clear example. The accusation against e.g., people in the Intelligent Design movement, is that they mix science with religion. However, also the other side mixes often science with religion. Clear example is of course Dawkins, who not only is of the main spokesmen for evolution, but also strongly fights against religion.
One other example of a mix of world-view with science can be found in the research done that tries to explain the origins of religion. Consider the paper Is Religion an Evolutionary Adaptation? by James Dow, published in Journal of Artificial Societies and Social Simulation, volume 11, no. 2 2. In this paper, the author tries to explain the origin of religion by evolution, using a computer simulation. The author gives in his introduction several scientific views on how religion could be originated. In Section 1.6., he writes:
One feature of religion that seems to stand out as non-adaptive is the belief in the existence of an unseen, unverifiable world. The existence of gods, spirits, and the like cannot be verified by the senses.This, however, is mixing world-view with science. There are many reports of people that have experienced religious phenomena. Whether one believes or disbelieves these reports is a matter of world-view. Indeed, besides the different "scientific" explanations for the origins of religion, there is another one, that one cannot rule out: maybe there is something... Maybe God or gods exist. And maybe, some people have experienced this, and that started the religion. And, maybe, God still exists, and still people experience Him, and maybe, this is one reason why religions keep on existing. (The Christian religion also provides an explanation why there are other religions, but I will not dwell on that issue here.)
Ruling out the existence of the supernatural for the investigations why a phenomenon as religion exists is adding a hidden assumption. Even worse, it can lead to a circular argument, and can make conclusions drawn false, as these conclusions are only correct when the assumption is correct. Then note, that the majority of people on this world have a religion that contradicts the hidden assumption.
In his abstract, Dow writes
Religious people talk about things that cannot be seen, stories that cannot be verified, and beings and forces beyond the ordinary. Perhaps their gods are truly at work, ...His phrase: Perhaps their gods are truly at work gives at least some hint on the possibility of the other explanation, but I cannot find this later in his paper.
At some moments, it seems that in the debate between atheist and Christian scientists, the Christians are asked to fight with one hand at their back. I think atheists should be aware of their own assumptions. Atheist evolutionsists seem as eager to do away the jumps in evolution as: we'll find a nice scientific explanation for it, as Intelligent Design-scientists like to see these as evidence for a supernatural Designer.
And, atheist scientist are very quick in disregarding all evidence that something supernatural exists. While the majority of the world population has a world-view that is not atheistic, while there are many reports on people that have experienced the supernatural, disregarding all that by directly assuming non-supernatural explanations, is not science, but a consequence of an atheistic world-view.
Then, in discussions I heard, and I have read, that religion talks about things that cannot be observed and thus are irrelevant for science. This argument against a role of religion in science is incorrect for at least three reasons. One I gave above: if the explanation given by religion is the correct one, disregarding it gives us a conclusion that is false. Then, many "normal" forms of science talks about things that cannot be observed. Historians tell about things that have happened, but that we cannot see anymore - conclusions are drawn from evidence from the past, but as we cannot time travel, how can we observe this past? Theoretical physics is another example. Finally, what religion talks about can be observed. But, the question is, do you want to? Suppose God exists - do you want to be a religious person in that case? If so, here is an "experiment" that you can carry out. It is however, a dangerous experiment: it can change your life. It can e.g., be done as follows.
Go to some place where you are alone. Close your eyes, fold your hands together, and say something, preferably loud, but otherwise in you thoughts, something like: Dear God. I do not know if you exist, but if you do, please let me know that you exist. If you exist, I want to know you. (Preferably, use your own words.)I should probably not call this an experiment. It is sometimes known as the prayer of the unbeliever. I know people that prayed this, and whose life has totally changed since then.
To conclude: there seem to be quite a lot of atheists that think that their world-view is backed up by science. However, there is the danger of the loop in the argument, and in fact, their interpretation of scientific results is caused by their world-view. I.e., if you first assume that you cannot make any metaphysical assumptions or conclusions in science, then you are also not allowed to make any scientific conclusions on the absense of metaphysics.
Finally, religion is actually not meant to give scientific conclusions. Religion helps us to deal with other big questions, like the purpose of life. Research after the origin of religion cannot be so clean without looking at what religion is saying itself, and it often appears that atheists fight a distorted image of religion - perhaps correct for some forms of religion, but incorrect for many. But more important than knowing the truth is to know our Maker himself. The Christian religion tells us that God loves us, rescues us, and that we can talk with him. Thus, religion gives answers to questions that science does not and does not need to ask.