User blog comment:PUNCHURPREGNANT/Gray and Silver Predictions/@comment-7418318-20140505173937

Not sure if anyone brought this particular theory up yet, but I don't feel like reading through 200+ comments right now.

Since the scars of Silver and Gray don't match up, I doubt they are the same person, but what if Silver is Gray's son?

That would explain the similar smell and that Silver seemed to know Natsu by sight, since Gray's children are bound to meet "uncle Natsu" sooner or later. Now if Gray was somehow unable to save his wife, Silver's mother, from whatever killed her, it would also explain why Silver hates Gray so much.

Not that I think this theory is very likely, but it'd make a lot more sense to me than Silver being future Gray himself.