Hello Jelena,
This problem is quite complex. There has been a very tough struggle for decades between the Lutherid Society (or the leaders there) and the descendants of Johannes Luther (1526-1574), who are doing everything they can to be recognized by the Society. I don't know exactly what it's all about in the end (probably also about personal animosities and/or money, as always), but the society still refuses to recognize the increasingly conclusive new research or at least to acknowledge it as a possibility and worth of a mentioning.
I'd rather say straight away that I myself have NOTHING to do with it and do not want to have anything to do with it. But, I have experienced and partly followed all the trouble elsewhere, and ended up in very unfriendly conversations.
However, I would at least like to point out here that there is also a different opinion to that expressed in the publications of the Lutherid Society. And (now I'm going out on a limb) I think they are much more conclusive than the old version.
But be that as it may. I'm just saying this so that perhaps people are aware of where this idea of missing sons comes from, and that it will come up from time to time. The fundamental research on this comes from the now deceased geneologist and Luther researcher Günter Luther, who "came from below", so to speak, found his link to Johannes Luther, and in this way shook up society's view of the world. As far as I know, according to their research, there is no longer a living bearer of Luther's name who is descended from the reformer directly, but only from his side relatives. So if Günter Luther were right, he would be a direct male bearer of the name; something that the other Lutherids lack. So perhaps the disputes are just a matter of offended pride?
The research has been very nicely traced and edited by Wolfgang Appell and is available on his genealogical Luther homepage. Everything else can be followed in detail there (It´s German, but can be switched into English by klicking on the flag). As I said, I'm only mentioning this to show the reason for the confusion, but I don't want to get caught up in it again :)