Breeding out atheism

...recently the most common explanation atheists give for religious belief is that such belief is evolutionarily favored: that is—for reasons which some atheists guess at, while others decline to speculate—religious belief in a person increases the chance that that person will pass on his or her genes to another generation.

Now, an atheist saying this immediately has a new problem, especially if he or she thinks that religious belief produces violence and intolerance—which is what many atheists, most notably Richard Dawkins and Sam Harris, have shouted from the world's rooftops. Anyone who holds both these views is in an interesting position, to say the least. Do we say that if I am violent and intolerant toward others I am more likely to pass along my genes—perhaps because I kill or injure those who do not share my religious beliefs before they can reproduce? If we do say that, then the atheist who protests against violence and intolerance will have to argue that we should behave in ways that do not maximize the likelihood of passing along our genes.

But this is a bad situation for an atheist to be in...If religiously inspired violence and intolerance are evolutionarily adaptive, and the blind processes of natural selection are the only ones that determine reproductive survival in the long term, then people who argue against religion and its accompanying pathologies are certain to diminish in numbers and eventually become totally marginal—nothing more than the occasional maladaptive mutation. The selfish gene will ultimately, necessarily, win out over the altruistic one.

Alan Jacobs, Christianity Today Books & Culture