Is racial interbreeding possible in Tamriel?

Question

Is racial interbreeding possible in Tamriel? So, do / could half-race individuals exist?

I know that Bretons are considered to be Men-Mer hybrids, but this is something that has possibly happened during the Mythic Era, so one could argue that there isn't a solid evidence about this (and besides that, in the timeframe of the games they are considered Men under all respects).

Is it possible, and are there known individuals, that have a mixed ancestry (not necessarily Men-Mer: also, i.e. Breton-Redguard, or Dunmer-Altmer, and the likes)?

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Note: I know that from a game perspective, you have to select from some predefined races and you can't make a "custom mix", but I'm interested in answers from Lore and not from game mechanics here.

Answer 1

_{Originally posted on Gaming.SE for a similar question.}

Mixed-race children like Jagar Tharn exist, but are exceedingly rare

The prototypical example of a mixed-race individual is Jagar Tharn, villain of the first game: Arena.

While there was a lot of in-universe debate over what he was, it was clear that he was an Elf mix, but didn't have human lineage (i.e. Imperial, Nord, Breton, or Redguard).

"I just don't trust that mongrel Elf. Part Dark Elf [Dunmer], part High Elf [Altmer], and part the gods only know what. All the worst qualities of all his combined bloods, I'll warrant." He snorted. "No one knows much about him. Claims he was born in southern Valenwood, of a Wood Elven [Bosmer] mother. […] Human blood seems to be the one missing component in Tharn's ancestry."

_{–The Real Barenziah, Vol 4}

The Imperial Library article on Jagar Tharn also weighs in:

He is said to be part Bosmer and part Dunmer.

I think this assessment is plausible, given that he has the skin tone of a Bosmer, but the eyes and height of a Dunmer.

To my knowledge, there are no other mixed-race individuals in the games.

Among species that can interbreed, children normally are the same race as their mother

The in-game book Notes on Racial Phylogeny states the following:

• Elves and humans can mate and produce fertile offspring
• Offspring of such unions match the race of the mother, but "traces of the father's race may also be present"
• Argonians and Khajiit are believed to be infertile with humans and elves
• Insufficient evidence exists to determine if Orcs are infertile with humans or elves

Regarding Orcs, Oblivion has a sidequest involving Agronak gro-Malog discovering that he is the son of a vampiric Imperial. So interbreeding between Orcs and Humans, even vampiric ones, must be possible.

Note that this report, especially with phrases like "traces of the father's race" does not match Jagar Tharn's situation, lending further evidence to mixed-race children being very atypical.

Answer 2

There is a book in game about it, called "Notes on Racial Phylogeny":

After much analysis of living specimens, the Council long ago determined that all "races" of elves and humans may mate with each other and bear fertile offspring. Generally the offspring bear the racial traits of the mother, though some traces of the father's race may also be present. It is less clear whether the Argonians and Khajiit are interfertile with both humans and elves. [...]

The reproductive biology of orcs is at present not well understood, and the same is true of goblins, trolls, harpies, dreugh, tsaesci, imga, various daedra and many others. Certainly, there have been cases of intercourse between these "races," generally in the nature of rape or magickal seduction, but there have been no documented cases of pregnancy.

So yes, it seems that men and mer can interbreed, but it is not as visible because the child of multi-racial couple takes the look of its mother's race

Answer 3

Yet there are Bretons, which are also called "Manmer" for a reason. They were 'created' because of the Direnni hegemony - Altmer - fraternizing with native human population.

Given that the book Notes on Racial Phylogeny actually confirms that some of the father's traits shine through in the offspring, the interbreeding must have persisted over generations and on a rather wide scale for a homogenuous race of humans with distinctly elven features (affinitiy for magic, slightly pointed ears) to form.