Well, I am not sure about this, I never was and I don't think many people will buy it. But today's chapter made it pretty clear for me.
I think Luffy is actually the son of "Gol D. Roger"
While Ace was the son of "Monkey D. Dragon"
And "Dragon" is aware of it.
Consider this, Dragon's family would have been in as much risk as roger's. When we saw the marines looking for Roger's family they might as well have been looking for Dragon's. Otherwise why would Garp arrive 11 months after rogue was due to give birth to Roger's child?
I mean he knew Rogue was going to have a child but he never visited the area until the day of his birth and that was according to the timeline a birth after 20 months? This makes me think Garp already took Luffy away to a safe place and came back for dragon's son.
Another thing to notice is garp said, "So, he inherited it after all!" when he watched luffy's display of king's dominance at marineford. But the funny thing is we have not yet explicitly seen Garp display CoC so far? so what was that inherited shit all about? Of course it is possible Dragon has this Haki, but there is a fifty percent chance that he does not.
Thirdly, in today's chapter Luffy himself said something really interesting "He does not look like me at all!"
And I have been going over this for sometime but every time you see Luffy give that wide smile, he resembles a lot more to yours truly "Gold Roger".
That's my theory :hyper::hyper::hyper::hyper:
There are many ideas you can easily discard simply by considering how they would influence the story, the development of the characters and the perception of the readers. If they screw majorly up either one of them, you can forget about the idea unless they author really would be completely oblivious. If what you say would really be true, you effectively destroyed multiple characters, in particular Ace. Ace has been haunted his entire life by the legacy of his father, it even lead to his death and only in his final moments he was able to come to terms with it. What you do is pretty much, on the moment Ace died, jump out of the shadows and yell it was all a joke and that his real father is Dragon. With other words Ace's entire life would have been a big, fat lie. Also as a result the Marineford arc would screwed over as it was all one huge mistake and to us both the emotions we associate with all of these events as the expectations we had for the future, like Luffy meeting Dragon, have likewise been screwed over. Luffy meeting his father is something very different than Luffy meeting his fake father, a fake father he wouldn't even have to meet as he doesn't have a connection with him anymore.
This alone makes it almost certain you can discard everything you just said as what you are doing comes down to raping the story. Secondly none of the arguments you used have any value:
Dragon's family didn't ran as much risk as Roger's. Why? Because one Dragon's threat grew throughout the years. At the point of Roger's death if he was already known, he wasn't considered that much of a risk yet. Secondly Dragon is the son of Garp. The reason as why Roger asked Garp of all people to take care of his son, was because he was certain he would and could keep him safe. If Garp already did that for his worst enemy, he certainly would do it for his own son and grandson. And the reason why Rogue kept Ace so long in her womb, was because than no one would ever think Ace was Roger's son as it should be physically impossible for a guy who died to father a child that was conceived long after he died. If Garp would have taken Ace while they were having their paranoid baby witch hunt and someone would have seen him, it would have been over. However after all the time that passed, no one would have ever thought that the kid Garp would have with him, was Roger's son. Sengoku made it perfectly clear that it was Rogue's obstinacy to keep Ace in her womb for that long is what saved him. You also can't know how many times Garp visited or didn't visit Rogue.
Garp was one of the strongest people of his generation. His son is the leader of one of the most powerful organizations in the world and unique in its nature as it opposes the WG. Now it's debatable whether Garp has the KD, but you can be certain that Dragon has it and even if that wouldn't be the case, just the facts alone that his father and grandfather are of that caliber, would be enough for Garp to assume his grandchild would be special. And then I'm not even including Luffy's maternal heritage, which is unknown atm, and the possibility that Garp knows more about the meaning of the "D" and what happened during the Void Century. Also we have never seen Roger using the KD. So your reasons to doubt that either Garp or Dragon has the KD apply as much to Roger as it does to them. Why would he expect that that Roger's son would have it, but not his own grandson?
Lastly Luffy had never any interest in his parentage to the point he even thought he didn't have any. And even after it was revealed what kind of an infamous man his father was, he didn't bother at all showing any kind of interest. That he said in this chapter that they don't resemble each other, is just Luffy being how he always has been. He finally can see his dad and then he comically says they don't resemble each other. Putting that aside, children don't have to look like their parents and Dragon doesn't look like Garp much either. So as an argument, this is very weak.
Originally many people were considering the possibility that Luffy was related to Roger. That however was skillfully exploited by Oda by introducing Dragon and turning Ace into Roger's son and Luffy's adoptive brother. The result? Orgasmic plot development. Now rewinding all of that would be pointless, stupid and anticlimactic. It doesn't do anything else than hurting the story, so you can pretty much disregard this completely.
