Originally Posted by Denville
True, but in any case illegitimate offspring of royals whether true or fake, aren't really royal….
I am not so sure. Sinde the UK passed the new bill on courtesy titles, it is possible for adopted children to use the same styles and courtesy titles as the blood children of a peer. So if the souverain wanted, it should be possible to adopt an illegitime child and declare them Royal, including the official style and precedence.
In France there is the historical example of Louis XIV. who declared his illegitime offspring not only as full members of the "Maison de France" and thus as princes of the blood Royal, but even declared in his will that if his legitimate descendants died, the line would continue with the illegitimate - thus declaring that it is the Royal blood that counts, not the question of who the mother was or if the child was born in wedlock.
Before that there are other examples of illegitimate children becoming the Head of a Royal House. Most notable William the Conqueror.
I agree that nowadays the "myth of the Blood Royal" does not seem to count for much (see the treatment the princesses of York receive at the hands of the media/Part of the public) and the way Royal Houses try to downgrade their members who are further down the line, but there is still the example of the Swedish RF, who accepts that female blood can give Royalty as well.
Same with noble blood: if my two grandmothers had been men, then I'd be named a Countess today (in my country this is just part of the name, so...), with both parents of the nobility. Because they were women, I only have some titled relations and noone in the family considers our part of it as "noble".