The attraction of evolution psychology of course is that it explains everything (and often without a whole lot of effort). Why are human beings violent sometimes and cooperative at other times? Because both have been selected for over time to be advantageous for passing on one's genes. Why do giraffes have long necks? Because it was selected for over time to be advantageous for passing on one's giraffe genes (better access to tasty leaves on trees and the ability to spot predators from a distance kept longer necked giraffes alive longer, or so the theory goes). Now in most cases there is little actual empirical evidence that evolutionary psychology is correct. It's mostly just deductive reasoning working back from what we can see in front of us to suppose the chain of events that led to this moment.
But here's the problem with evolutionary psychology. It completely invalidates the concept of desire. If all of our desires are just tricks our genes play in the effort to replicate themselves then human beings are just viruses, no better no worse, and, as least as far as I can tell, viruses don't have the capacity to love. Love is the greatest thing we have on this planet. It's the only thing that makes life worth living. It is why we are here. And if love is just a trick that our DNA plays on our minds, if it has no deeper meaning than simply replication of a code for the self-preservation of a string of chemicals that we never actually see and don't particularly identify with, then life just got a whole lot emptier. And then that becomes the Achilles heal that dooms evolutionary psychology as a discipline. I just don't think that a theory that has the potential to invalidate the concept of love can ever win widespread acceptance. The cost of embracing the theory is too high.
Interestingly, (this didn't come to me until just now), this little rant is also an interesting endorsement of gay marriage. Gay marriages (particularly gay male marriages) are the only ones in which we might reasonably believe that it is not just the replication of genes that is being served, but rather, that there might be genuine love for another person. Marriages among senior citizens would fit this argument too. It's the exact inverse of the conservative argument. The conservative argument turns human beings into viruses, with the reasoning that 'our only purpose is procreation, not love.' But everyone knows that love is the only thing really worth living for and the best reason to get married. Conservatives, by making an argument based on reproduction, thus become slaves to their DNA -- while the rest of us try to build a world based on love (which is also the foundation for morality, ethics, and religion). Completely fascinating.