Well, Sylar also said that he wished as a kid that his family wasn't his family...maybe he was put up for adoption or raised by his mother and a stepfather?

As for fic...I was thinking about writing a crack!fic about it...

Peter: Hey, Nathan! Think I'm embarassing? Meet our half-brother! *to Sylar* Dude, seriously, will you stop trying to cut my head open for one damn minute?!