Racial mixing vs separation

In this post (part of a series on race in fantasy), I will discuss the logic of what happens if different fantasy races can interbreed, and what world building options are therefore open to a logical world-builder.

Two disclaimers before I get into this:

  1. I am talking about biological heredity: what modern science calls genes and what fantasy tends to call something like bloodlines or ancestries. Cultural inheritance and race as a cultural phenomenon are more complex; I might do another post about them some time.
  2. I am in no way suggesting that real world races work, or should work, in the way I am about to discuss. The vocabulary of hybridization, half-races, bloodlines and so forth is shared with a lot of discredited thinking about real world race and heredity which I do not endorse. I’m just pursuing the world building logic you get into if, like Tolkien’s Middle-Earth or a Dungeons & Dragons rulebook, you start with the idea that there are distinct and essentially different races of people in the world that meet and interact. I don’t think that the notion of essentially distinct races describes the real world well: in reality, ‘race’ is a socially constructed set of concepts that we apply to individual people and to a continuum of populations, whose similarities and differences are actually much more complex. (Edit: my next post goes more into essentialism.) Furthermore, I am going to use a number of sentences along the lines of ‘in order to keep races separate you must…’ This does *not* mean that I think races ought to be kept separate, not necessarily in fantasy and certainly not in real life. I’m just setting out an if-then argument about world building.

If many of the common fantasy humanoid races can produce hybrid offspring (which is canonical in Dungeons & Dragons 5e, as noted in my recent blog post), and those hybrids are themselves fertile, with each other and with their parent races, what happens then? I think there are two possibilities:

  1. all the races that participate in this interbreeding blend into one, with individual variability extended to encompass fantastical features but without separate orcs, elves and the rest; or
  2. the races remain separate because something prevents the hybridization actually happening.

If the latter does not apply, the former will inevitably follow as the bloodlines of each race get into the populations of the others.

So (if you wish to have a logic to your world; obviously you always have the ‘it just is, don’t overthink it’ option) these are your choices: abandon the sub-Tolkien genre’s traditional separate races, or be clear why they don’t mix.

Let us look then at the ways in which a world builder might ensure that hybridization remains rare and/or individuals of multi-racial heritage do not themselves have children.

Lack of contact between races

This would be an effective way to make sure that races do not interbreed: have them in different places or times, never coming into contact with each other. However at this extreme, it means that no story in such a world can feature multiple races interacting or alongside each other, which you might think defeats the purpose of writing multiple races to begin with.

So can you relax this assumption somewhat? I don’t think you can relax it much in the long term without in effect removing it completely. It has been demonstrated mathematically (the arguments are summed up here with references to the technical literature) that with a human generation length, all members of a even a large well-mixed population share at least one common ancestor less than about a thousand years back, and are all descended from *every* individual (barring those who have left no descendants at all) less than two thousand years back. Completely isolated populations do not share common ancestors, but even a limited genetic interchange produces universally shared ancestry within timescales not much longer (point brought out in this other discussion of the same research).  So bloodlines mix completely on historical timescales; to preserve races as distinct, the amount of interbreeding *that has ever occurred in your world’s history* needs to remain a small fraction of the living population.

I think then that there are two kinds of limited-contact story possible. One where cases of contact with other races (ocean voyages or whatever) are exceptional, countable events that do not become regular at even a low frequency. And the other where contact between races may be a recurrent feature of the setting but has only recently been made, so that there has not yet been time for much interbreeding to occur. Either case might make for a story worth telling, if you feel that your storytelling or gaming purpose is served by a tale of exceptional contact between races otherwise firmly separated from each other. It might also be interesting to pursue the implications for culture and world building of such racial separation and lack of common ground.

Physical impossibility of having children together

This is perhaps the assumption that best enables a world builder to otherwise retain the tropes and conventions of sub-Tolkien fantasy. It means people from different races can come into contact with each other, trade, talk, contest, fall in love and all the things people do, but without having children together, and so without mingling the races. (Culture would be another matter but, as I say, this is something I’m not attempting to discuss at this time.)

It would mean that canonical DnD races like the half-elf and half-orc, and canonical monster types like the half-ogre, need to be deleted from the world. And a more scientifically minded world builder might like to invent reasons it should be true that otherwise similar peoples cannot have children together.

If couples or partnerships including people from different races therefore cannot have biological children and are not happy about this then they might adopt, they might seek a magical or technological way to become fertile (unsuccessfully or at least very rarely, to preserve the separation of races), or they might simply remain unsatisfied. They might also be reluctant to form such partnerships if biological children are what they want. These dynamics could generate or be built into stories for you to tell in your world.

The alternative version of this scenario is that hybrids between races do exist but are themselves physically infertile, so that their bloodlines do not get back into those of the primary races. Similar stories arising from the desire for children could be told about these individuals or partnerships involving them.

Lack of desire to mate

This is, I feel, a difficult one to believe in. Logically, if people of different races do not recognize each other as potential mates, then they will not (or not often) reproduce even if they would be capable of conceiving children. But to make it at all plausible that none of the various races would choose each other as mates I think would require some radical redesigns to the form and/or psychology of the near-human races as traditionally portrayed in games and fantasy fiction.

Social taboos on having children together

This is a little more plausible. In society with different races, there could for some reason be strict prohibitions on relationships between races that might lead to multiracial children. There is, I believe, some evidence from genetic studies in India that the caste system there has resulted in considerable isolation of parts of the human gene pool from others in the same region. But the isolation has not been complete and I doubt that even this scientifically-measurable restriction of gene flow could preserve racial separation to a Tolkienesque degree (the article on the maths of common ancestry touches on this issue too).

You would also need to consider why and how a multiracial society would impose strict taboos on mixed marriages. What kind of values and structures would give rise to this rule? The Indian caste system is tied up with occupation, religion and a number of other factors. Legal prohibitions on mixed marriage in many states of the pre-Civil Rights USA, Nazi Germany and apartheid South Africa arose from officially-endorsed white supremacism. And what enforcement measures or practical considerations discourage those who would surely wish to break society’s rules? In Tolkien’s world, there is a divine decree that the Elf partner joining with a human must forsake their unending life and become mortal, helping to explain his decision to have only three mixed marriages in Middle-Earth’s long Ages.  

No barriers to racial mixing

If none of the above barriers to racial mixing apply, then I think within a relatively short period of history (especially considering the tendency of fantasy worlds to have deep histories, stretching back ages) racial mixing will happen. In the first generation after contact between two originally-separate races, there will be a limited number of half-and-half hybrids. The following generation there will be more hybrids, and some quarter-three-quarter hybrids. And so on. As the generations roll by, there will be fewer and fewer of the original unmixed races left, and eventually none. Races with very long life cycles would persist for longer, as a given number of centuries means fewer generations for them, but even they would blend in eventually.


So hopefully that works through some of the world building implications that you might see under different factors that prevent or allow racial mixing. I feel that a ‘vanilla’ D&D-style fantasy world, in which the various races can mix and do mix to create half-elves, half-orcs and half-ogres, but also somehow mix no further than that and persist as separate races for thousands of years, runs into logical difficulties.

The barriers to mixing that we have explored would have wider implications for the society that supports such barriers and may spark your creativity and the distinctiveness of your world.

Or you can follow the implications of a lack of barriers, and imagine what a world would be like in which fantasy races are mixed together. I plan to return to this in a future post.

As always, let us know your thoughts in the comment section.

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