@mipmip, Probably we interpret the question differently. I take it from the point of view of Darwin's evolution, where "good" mutations are transmitted from parents to children by genes. If you take the child of the two most religious persons in the world and give to an atheist family to raise, I must consider it will grow an atheist.
Of course you need to be religious in a Muslim country to marry (or at least pretend to be) and this is good adaptation to the situation but I don't consider this evolution in the sense of biological evolution. There is no such thing as the religious gene I believe.

I am not certain I fully understand the question but if I get it correct my answer is No. When religion first appeared in the early civilizations I doubt it that people who were religious had better chance for survival and reprodruction.
Probably the only period when religion was interfering with natural (or artificial) selection was during the Holy Inquisition - the burnt the non-believers and and the atheists.
But I don't believe that nowadays you have lesser chances for reproduction if you are atheist.