Can only men pass on the will of D.? So I was wondering how the will of D. is passed on. We have seen three cases where the will of D. was shown to be passed on and they were all from generation to generation by birth. Luffy got it from Dragon, Dragon got it from Garp and Ace got it from Roger (and Rouge?). In each case the will was passed on along with the last name. Now this made me wonder. Is it merely in a name? Or is there more to it?

Ace would probably be the best example. He chose to go through life using his mother's name Portgas D. Now what if Ace's mother would not have been a carrier, would Ace have not have had the will of D because of his name? Or what if Ace's mother married some other guy who didn't have the will of D, would she be unable to pass it on, because children are given their fathers name? This sounds pretty sexist to me, so it made me wonder whether just having the right surname is enough for someone to have the will of D or if there is some other way to become a D or to pass on the will of D?

If there isn't, the will of D will probably die out pretty soon...
OK, this is a hard question and not much is released about it till now.

Here's a short summary:

There are multiple characters in the One Piece universe with the letter D in their name:

Monkey D. Luffy, Monkey D. Garp, Monkey D. Dragon, Gol D. Roger, Trafalgar D. Water Law, Marshall D. Teach, Portgas D. Rouge and more.

In the Wiki, I found this:


  Whitebeard noted that killing the bloodline of a D does not put out the flames that they (a person carrying the "D") carry and someone else simply will pick it up one day


So there, the "D" is linked to someone's name and not to the bloodline itself. So this would mean, you can't wipe out the will of "D". It will appear somewhere else in some other family.

Law said:


  What's the Dark King thinking this time? The Will of the D. will almost certainly call up a storm again


and also the Gorosei mentions:


  "D" means danger


So we can say this question is not surely answerable right now. But I'm quite sure this "D" is not just about bloodline. I agree that in the Monkey family the will is given to the next generation, but I don't think it's just about the blood, it's more than that.

Update: I also found a pretty interesting where "the will of D" could mean "the will to die". Reddit


  Gol D. Roger, gave himself in the arms of death to inspire a new generation of pirates. Portgas D. Ace, fought for the honor of his captain and died saving his brother.
  Let's take a look at Marshall D. Teach. While fighting with Whitebeard he showed clear signs that he feared death. Minutes later we get a speech from Whitebeard telling us that he was not the man Roger is waiting for, and that he was also not a true D.*


You can find this in chapter 576.




At this point, Whitebeard speaks also about the "bloodline" and not just about the name. And you also never know how correctly translated this mangas are.
I know its not a clear answer, but maybe you found some aspects which helps you.