@Frank Apisa,
Well according to what I read it is because the cells become disorganized once they are separated, through a cut or whatever, and cannot repair themself back to "normal" because of the disorganization it causes.
You say there is no evidence either way whether there is or isn't a God. We know our body's can only do a partial healing of itself, which creates a scar. So what about someone's scars being healed... Completely... As if they were never there? Would that be evidence enough for you or anyone else the possibility that there might be something bigger than we thought out there, working on our behalf?