Sven Jaschan, the author of the Netsky and Sasser worms, has been interviewed in Stern magazine. The interview gives an impression of a young man typical of young virus writers who are caught: a certain naivety, a bungled attempt to use a virus to fight a virus, an inability to understand the far-reaching consequences of releasing self-replicating code. In the interview, Sven also alleges that his siblings and many of his classmates knew what he was doing, and even encouraged and helped him. This shows the need to include information security in the school curriculum, starting when children first touch a keyboard.
Of course, this tells us nothing about the virus writers who do not get caught.