nature vs. nurture

Today at MOPS a question was posed about nature vs. nurture. If there is one thing I have learned about having boys, it's that you can nurture as much as you want, but nature will have its way. I have not nurtured the fascinations with trains or garbage trucks, but still there is a natural fascination that I cannot break. It's unreal.
In no way did I attempt to get my child to learn the names of each Thomas the Train engine. In fact, until I had boys, I didn't even know there were more trains than Thomas. I most definitely did not encourage them to want all the trains, especially at $15 a pop (I have actually considered taking up wood carving, because those trains are so ridiculously priced.) And I do not encourage them to build tracks every day. Yet still...these things occur.
Garbage trucks are a whole different story. I now own four, ranging from hotwheel sized to half of Brayden's size. The boys have recently revamped their fascination with these and love to "Play garbage together," as Gavin says. They load up the plastic food, french fries being the most fought over, they apparently make for good trash, then go take it to a place to "dump, dump, dump." They'll play garbage trucks for up to an hour together. Not to mention, they got a garbage truck video (VHS, none the less) at the video store and it's actually the first video Bray will sit all the way through. Gavin watches it every night. It's crazy, annoying and they love it! No, I had nothing to do with teaching them the difference between the front loader and heil side loader, but they found out and they can point them out on the road. Nature took it's course.
As for nurture, I think I am the one getting nurtured. I can now name multiple Thomas engines and sing quite a few of the songs. I make a mean track, using all the track we own. I know how to play garbage trucks..."Tonka sanitation services, ready for pick up." I can quote the quotes from the buttons and I am eerily good about recreating the lift and dump noise on the medium sized front loader.
Do I let the boys play with dolls? Sure, we bought one when Bray was born. Gav knows what to do. Feed it, burp it, swaddle it and find a truck to drive it in. The last part he came up with on his own. Brayden found it once. He'll hug it, set it down, then run over to his matchbox truck, wrap it up in a small blanky, pick it up and pat it night night.
I don't know much, but I do know the question made me laugh. I am doing my best to nurture many things, and I believe you can. But we do have a healthy quantity of things in this house that arrived by nature and nature alone.