True story: When my son was 5, he liked the Cartoon Network and Nick Toons, and was constantly bugging me to switch the channels for him. He already knew how to read and how to surf the web a bit, and knew the channel numbers for his two favorite channels. So one day, I showed him how to use the remote, tossed it to him, and went off to take a leak.
I walk back into the living room, not two minutes later, and my son is glued to the TV. My brain goes "Wait a minute. Something is wrong here.". I think I was just stunned, because it took me a good 20 seconds to realize that in the time I was gone, he had figured out how to open the channel guide, find the adult programming, say he was an adult, and then buy porn.
Like father like son, I guess.