that bits and pieces of it were flying off with every murder he did then there should have been dozens of accidental horcruxes all over Britain. There is also the fact that Horcruxes are described as being quite indestructible to anything short of fiendfyre and basilisk venom. Harry on the other hand is injured dozens of times throughout the course of the series. Granted that an organic living Horcrux would be different, shouldn't it at least have toughened him up just a bit. At best, Harry was possessed by a bit of Voldemort's soul. And I'm not even getting into how his mother's protection which was strong enough to burn Quirrell into ash did nothing to prevent Harry being turned into a Horcrux.
Even in canon, there really is not much evidence given for the fact that Harry is a Horcrux. Ignoring Dumbledore's opinion, all we really know for certain is that Harry and Voldemort have some sort of a connection and we have the little deformed baby in Kings Cross Station after Harry dies. Does this really mean that Harry is a Horcrux? Why can't Harry be the victim of a possession instead? For those who will no doubt state that just having a bit of Voldemort's spirit inside you is enough to make you a Horcrux, I ask - What about Quirrell? He was possessed by Voldemort. Was he a Horcrux? If he was then Harry should have been able to destroy any Horcrux just by touching it.
Finally, why didn't Poppy Pomfrey ever realise this? Who knows? In canon, she is described as a talented healer but she works as a school nurse. Perhaps she is not qualified enough to detect this. Perhaps she never looked. Perhaps she was always more concerned with treating his immediate injuries to worry about a scar that was a decade old.
~oo00oo~
A/N 2: I had to put this in because I was getting too many reviews speculating about this. Patil is a very common Indian surname and the Dr. Patil in this chapter is not related to Padma and Parvati Patil. In retrospect I really should have gone with a different name.