People more moderate than I have said that religion should be tolerated, in spite of the incredible damage it does to society, because of the joy it brings to individuals. Normally I would dismiss this as piffle, and strike them soundly about the skull with whatever came to hand, but today religion has brought me a certain happiness.
Let's assume for a moment that we are evolved from some sort of precursor species. One that perhaps did not have all of mankind's intelligence and capacity for self-delusion. That creature would behave much like every other animal demonstrably does - that is, attempt to find food and breed. Maybe the males would help look after their offspring, though that would depend on whether the food available and the level of danger in the environment would make it a better bet to father and abandon many children, or protect and nurture one to developmental maturity.
Assuming the latter is the case, which seems likely as this is how humans tend to behave, males should show a preference for partners they think to be loyal, reducing the chances of their wasting time and resources to raising another male's child. This brings me, in a roundabout way to my point.
One of the most obvious ways of assuring a female was, if only to begin with, faithful, would be if she was a virgin. Therefore males that actively selected for this (I'm assuming this precursor to be social because of overwhelming evidence that I'm not listing here) should have more luck reproductively, and a greater chance of passing their genes on.
The huge, belly-laugh inducing irony therefore is that one of the traits of the major religions (no sex before marriage) held up as an example of how humans are somehow inherently different from other species, that they possess some spark of the divine, is simply a ritualised form of a demonstrably evolutionary trait.
I'll be chuckling under my breath for weeks.