The Xyrillians are a neutral, humanoid race from the Alpha Quadrant, first encountered by humans in 2151. They live within an egalitarian society in which the leader, or Primal, is selected by democratic vote from a pool of 20 objectively chosen candidates. While Xyrillians biology does permit two separate sexes based upon reproductive function, the “male” and “female” sexes are opposite those encountered in many other humanoid species; genetic material does combine as a result of sexual reproduction, but the fetus gestates inside the male Xyrillian. Most uniquely, Xyrillian biology allows for transmission of this characteristic to sexual partners from other species; sexual reproduction between a Xyrillian female and a compatible male from another species may result in the impregnation of that male, regardless if males of his species are capable of carrying a fetus.
Xyrillians are not warlike by nature and are fairly insular; they have rejected all inroads regarding alliance with any large Alpha or Beta Quadrant power, and even though they are technologically advanced, their sphere of influence is quite small and centered upon their fortified homeworld. The Xyrillians developed several technologies ahead of humans and other Alpha Quadrant species, including holodeck technology.
To learn more about the Xyrillians, visit their wiki page!