There is a bit of self-selection of atheists becoming Biologists. In other words learning Biology doesn’t turn people into atheists, it is just more likely that people who are interested in Biology are atheists than the general population. This is probably due to religious zealots saying that Biology denies God, therefore those who deny God seek out the information that the zealots say disproves God.
Sigh. There are actually four cases, using a broad brush, among those interested in the issue.
Those who self-select for Christianity due to wishful thinking.
Those who self-select for Christianity out of masochism.
Those who self-select for atheism out of wishful thinking.
Those who self-select for atheism out of self-loathing / pessimism.
The accuracy of any particular model is unaffected in either direction by ad hominem arguments about its proponents.
The problem with Christianity is that (since it is dealing explicitly with the supernatural is that it is not amenable to falsification by the ordinary methods used in empirical study. By the null hypothesis, Occam's razor, etc., the empiricist says, "Nope. No gods here."
The crux of the matter is whether or not one will ever admit the existence of anything without 'sufficient evidence'; what constitutes 'acceptable evidence'; and how one judges the risks of logical inconsistency (differing standards) vs. the risks of falsely accepting hearsay or falsely rejecting something which (after the fact) turns out to have been true all along.
The whole issue quickly gets too hairy and messy to deal with succinctly in a format such as this...
To return to your topic of self-selection, etc., have you googled Project Steve ?
Cheers!