Single-Gender Races

[AlexanderHowl]

One of the staples of speculative fiction is the single-gender race. Now, single-gender species do exist in nature, they generally reproduce by parthenogenesis (though some have more exotic forms of reproduction), and a number of them actually mate with males from outside of their species because they require sperm to trigger their parthenogenesis reproduction. While there are no known mammalian single-gender species, it is not impossible, and a single-gender sapient species could evolve under unusual circumstances (or be the result of genetic engineering).

Now, there are generally four broad categories of reproduction for single-gender races in fiction. First, there is unassisted parthenogenesis reproduction by a female-only race, where a member of a race self-fertilizes through one method or another. Second, there is assisted parthenogenesis reproduction by a female-only race, where a member of a race require another individual to trigger parthenogenesis, ranging from sexual activity to an actual genetic contribution. Third, there is interracial sexual reproduction, where a member of the race breeds with a member of another race, and the resulting children take after the parent that they share their sex with (boys taking after their fathers and girls taking after their mothers). Fourth, there is hermaphroditic reproduction, where the members of a single-gender race are capable of fertilizing and being fertilized by other members of their race. You can also end up with single-gender races that have multiple reproductive strategies, such as a single-gender race that can reproduce through hermaphroditic reproduction also being capable of interracial sexual reproduction.

In GURPS, the Medusas of Banestorm are probably the best example of single-gender races, a female-only race capable of interracial sexual reproduction, but there are other examples. I was wondering if anyone had any single-gender races that they had created that they were willing to share? Do you like using single-gender races in your games or do you think that they are silly?

[David Johnston2]

In my setting of Sowan, witches are single gender, in that they have sex with human males but can only give birth to females with Magery. They did have a male-only counterpart known as sorcerers who could father both male and female offspring but only the males had Magery. However as of the time where I set it, the sorcerers were supposedly extinct, having succeeded in making enemies of the witches, vampires, and werewolves all at the time without making any friends among the ghosts and immortals. A century later they still seem to be gone but people with Gadgeteering have cropped up and it remains unknown whether the power of the sorcerers has taken a new form after being passed down about a few survivors of the purge or the world just decided that something had to fill the empty space.

[The Colonel]

Would we count symbiotic mates like real work anglerfish or the Pak'M'Ra from Babylon 5?

[AlexanderHowl]

Not really, as they are once independent members of the same race and are required for reproduction (there are two sexes, the second sex is just used for reproduction). I can see the confusion though, as there is only likely one socially constructed gender in that race, and I can see outsiders making a mistake by assuming that the race was a type one. A similar confusion could occur with outsiders when encountering species without multiple gender pronouns that do not have very pronounced secondary sexual characteristics (like the dwarfs of Discworld).

[vicky_molokh]

I wonder whether a race which is single-sex for the purposes of gamete production, but can have external anatomy more in line with the two sexes of humans, counts as single-sex for your purposes. (I have one like that in my current setting; it is of course hybridogenetic.)

[whswhs]

Aren't there also self-fertilizing hermaphrodites? And then there is the case of alternating-sex hermaphrodites.

And are we talking about (biological) sex, or about (culturally constructed) gender? Those are not the same thing and raise different questions.

[SilvercatMoonpaw]

One variant I've thought if is where the "race" is actually a variant genetic condition that is dominant in the Mendelian sense: they mate with members of a different race because those are actually members of their own species. Somehow the meiosis never mixes any of the dominant genes with recessive ones, so any child that inherits the dominant genes comes out as a member of the single-sex race even if they have the sex chromosomes of the opposite sex.

This version has a possible interesting consequence: there are three possible offspring types:
1) Child of the single-sex-race parent.
2) Child of the non-single-sex-race parent who is the same sex as that parent.
3) Child of the non-single-sex-race parent who is the opposite sex from that parent.

When you use this variant one can speculate that if you don't get #3 that something in the single-sex-race parent genetics prevents this. Works better if the single-sex-race parent acts as the mother: their body somehow rejects fetuses of a certain combination. (And if you want to encourage even more of the single-sex-race you can say the mother rejects any fetus not carrying those dominant genes.)

So what you have here is an entire parasite genetic code.

[vicky_molokh]

Originally Posted by SilvercatMoonpaw

Works better if the single-sex-race parent acts as the mother

Why does it work better? Is there something wrong with the single-sex species of male-only clams which lives in one of our oceans?

[SilvercatMoonpaw]

Originally Posted by AlexanderHowl

Now, there are generally four broad categories of reproduction for single-gender races in fiction.

Five if you include a race that gets its new members via an outside source.

[SilvercatMoonpaw]

Originally Posted by vicky_molokh

Why does it work better? Is there something wrong with the single-sex species of male-only clams which lives in one of our oceans?

I meant the "stops certain gene combinations from being allowed to survive": internal fertilization gives extra time for some mechanism of destroying "undesired" combinations.

Of course that assumes internal holding. If the species reproduces via external fertilization I don't even know how that'd work.

It's kind of hard to keep all forms of reproduction in mind when talking about this.