Carmen cautioned me on my supposition that the apparent male propensity for intraspecies and interspecies violence has a genetic component. This hypothesis, and others like it, she says, don't meet the two hallmarks of the scientific method: Ockham's Razor and refutability.
As for Ockham's razor: The very resilience and vigor of the nature/nurture controversies would seem to suggest that the razor does not cut decisively either way. If anything, when it comes to male violence, I would opt for the parsimony of genes.
As for refutability: It is true that the hypothesis is for the time being "thinly sourced" (I love her journalistic phrase). There are, however, many studies of nature/nurture based on behavioral characteristics of identical and fraternal twins, which, taken together, seem (to me) to give genes a boost. As scientists delve ever deeper into the genome they will surely be in a better position to empirically resolve the debates.
In other species, examples of manifestly genetic complex behaviors abound, for example, the spectacular unguided flight of juvenile red knots from northern Canada to Tierra del Fuego, or the migration of monarch butterflies. I would be surprised if some human behaviors did not have a genetic basis.
But I agree completely with Carmen that weak scientific claims of genetically-based behaviors, let loose in the world, are fodder for mischief, especially in matters of gender, race, sexual orientation, and so on. All of us of a certain age remember the uproar that met E. O. Wilson's Sociobiology, and the impassioned rows between the Gould and Wilson camps. So, yes, let's be cautious. I hope that whenever I have opined on these matters I have used qualified language.
In any case, we are not prisoners of our genes. Complex cultures are the hallmark of our species. Are males more inclined by nature than females to shoot and kill? I don't know. I do believe we can pass laws to protect birds. Are females less "analytical" by nature than males? I don't know. I do know my daughter is a more successful analytical scientist than I could have ever been -- and I have some wizard granddaughters too.