Scientists, take a break. I've got this one figured out.
Geekiness is passed on from father to son.
Xander (for those of you who don't know, that'd be my 3 year-old son) actually likes the same things that I do. Sometimes after dinner I'll put in a DVD for us to watch. Sometimes I play the Dad Card and decide that we're watching what Daddy's watching and if you don't like it you can do something else. Sometimes, like tonight, I let Xan pick. He totally asked if we can watch "Buffy." When I asked him why, he said "I like Spike." It's really cool to see him develop interests and be able to understand what he's seeing on the screen. He'll tell me things like "There's Willow" or "Uh-oh, they're fighting." The best part, of course, is that I have a 3 year-old who requests that we watch "Buffy the Vampire Slayer." Father of the year? I'm leaning towards "yes."
nature or nurture? either it's genetic, or comes from observation at an early age. my dad is a communications lawyer, but I certainly don't feel an innate drive to study the intricacies of the FCC. I've just seen it and it's interesting. I think we're genetically predisposed to having certain skill sets and strengths, but how we channel them into our own interests depends on largely on what we are exposed to.
Either way, I think it's great that my kid enjoys the same things that I do. Whether it's nature or nurture it makes a guy feel pretty good.