[Corsair_Caruso]

Originally Posted by Mithalwen

I would dearly love to know more about Gil-galad, not just a definitive resolution of the "Whose the Daddy?" issue, but he ruled a huge area for an age of the world and the hints are tantalising.

Originally Posted by Belegorn

I don't know if it's much but I believe there's a letter Gil-galad wrote to the King of Númenor in Aldarion and Erendis.

Originally Posted by Mithalwen

That is one of the tantalising hints.

I've documented my opinion on the parentage of Gil-galad in an essay I'm writing on Galadriel, in an attempt to come up with a consistent history for her and her family.

Taken from Corsair_Caruso's essay, left unquoted (for the most part) for ease of quoting in response

Gil-galad's ancestry is somewhat of a contentious issue. In The War of the Jewels, C. Tolkien stated that Gil-galad as Fingon's son was "adopted after much hesitation," and that it "was not in fact by any means the last of my father’s speculations?" Later, in The Peoples of Middle-earth, C. Tolkien stated that Gil-galad as the son of Fingon (as given in The Silmarillion and referenced in the letter from Gil-galad to Tar-Meneldur in Aldarion and Erendis) was an outright error.

Apparently Gil-galad's ancestry was as problematic for the Tolkiens as it has been for his readers. C. Tolkien states that Gil-galad's parentage changed many times throughout his father's writing process. He was alternatively the son of Fingon, Finrod, or Orodreth. The changing of other characters' placement on the family tree, including Orodreth's, didn't help either.
C. Tolkien reports that in 1965, "my father suggested that the best solution to the problem of Gil-galad's heritage was to find him in 'the son of Orodreth'..." who in this text is described as "Finrod's kinsman and steward," and Gil-galad subsequently called "the son of Arothir, nephew of Finrod," with Arothir being an alternate name for Orodreth. Finduilas' parentage was unamended by Tolkien, and thus she became Gil-galad's sister.

C. Tolkien was quite firm that this assertion superseded that published in The Silmarillion:

There can be no doubt that thus was my father's last word on the subject; but nothing of this late and radically altered conception ever touched the existing narratives, and it was obviously impossible to incorporate it into the published Silmarillion.
[...]
Much closer analysis of the admittedly extremely complex material than I had made twenty years ago makes it clear that Gil-galad as the son of Fingon was an ephemeral idea.

So, C. Tolkien admits that he chose not to include this change, though it was clear that his father had firmly changed his mind on the subject, and furthermore that the parentage included in The Silmarillion would have been different as a result of closer study of his father's notes.

Those familiar with Aldarion and Erendis in Unfinished Tales will remember that the salutation in Gil-galad's letter to Tar-Meneldur begins with "Ereinion Gil-galad son of Fingon," but C. notes that this was an editorial choice on his part, with the original text being "Finellach Gil-galad of the House of Finarfin."

C. Tolkien's statements to the error of the earlier stated and more widely known parentage of Gil-galad and Orodreth notwithstanding, he retained the genealogy as stated in The Silmarillion for the publication of The Children of Húrin. Nonetheless, I have chosen to make the suggested alterations for the purposes of any of my Arda narratives, thus...

Finarfin's son are Finrod (died without issue), Aegnor (died without issue, due in part to his love for the mortal woman Andreth), and Angrod. Angrod was the father of Orodreth, who succeeded his uncle Finrod as king of Nargothrond, and whose children were Finduilas and Gil-galad. This, in my opinion, also clears up the issue of inheritance of the High-Kingship of the Noldor in Exile. While Gil-galad was the son of Fingon, it left people scrambling for justification as to why Turgon inherited the title of High-King when Fingon died, rather than his ostensible son, Gil-galad, leading some to claim that the inheritance must have gone first to brothers before sons. This, while possible, seems to me inelegant. With Gil-galad as the son of Orodreth, we have a much more traditional line of inheritance.

Fingolfin >son> Fingon (died without issue) >brother, next oldest son of Fingolfin> Turgon (died without a son) >closest relative by male descent/first-cousin twice removed>Ereinion Gil-galad.

end

So, I'm convinced that Gil-galad should be regarded the son of Orodreth, who is the son of Angrod, with the above as evidence.