A race composed of a single gender that is not asexual. To reproduce it needs the genetics of a specific sex of a different dual gender host race. Offspring are not a mix but are new full blooded creatures of the parasitic race (required to keep the race viable).
Only found in fiction and not in nature, due to the population balance required to ensure both races remain viable. The parasitic race cannot reserve too many of the host race's compatible gender as there must remain enough host-host pairs to continue to create more of the host race to supply the parasitic race for the foreseeable future.
This is not just normal inter-species reproduction, due to the dependence and full-blooded offspring produced. Where normal inter-species reproduction is two independent species that can intermate (like dog breeds), and where parings produce half-half offspring. The ability to intermate is not this trope, while genetically-required-intermating is part of this trope.
Acceptable exceptions, are allowed as long as the dependency to maintain viability is maintained.
- The One-Gender Race could have two genders where one gender is non-functional/sterile.
- The offspring could be one of the dual gender race, but must be a rare occurrence, or have some disadvantage keeping the One-Gender Race dependent on the Dual.
- The dual gender race (though commonly is) need not be a signal race, and may be from a group of different but similar/intermating dual gender races.
If the host race was not a dual gender (yet still not asexual) then it would be two One Gender Races
are really the male and female versions of the same species, with a health dose of Bizarre Sexual Dimorphism
While this trope does fall under the very broad category of One-Gender Race
, it's a specific yet commonly found subset significantly different from the other possible facets of One-Gender Race
Thing on Girl
Japanese H-Manga, have a common theme of tentacles/demons/insects impregnating human/humanoid women, that later give birth to more of the monster. This can be misleading as many of these lay eggs in the human, and supply seed, and thus are NOT this trope.
Sexy on guy
Cute/Seductive/Hot furry/monster/animal women who require human male seed to create offspring.
A tentacle creature lays its eggs in a human female, and then through pheromones attracts human males to fertilize the eggs (the human female is only an incubator). While it does make use of both host genders it's only genetically dependent on one.
A race and its host race are both this trope. While the pairing can produce its host's host race the survival rate is next to none, and it is unable to produce any of its direct host's race. While its host race is a mono gender due to parasitic nature of the host race, the host-(host's host) pair acts like a dual gender.
While most Parasitoid
creatures don't fall under this trope, this does as the offspring have some genetic material, and minor characteristics of the host. They are also a single gender.