The Eyren are a humanoid species native to the planet Eyren.
In the early 21st century, the male population of the Eyren was infected with a mysterious genetic disease that effectively made them sterile, and made future generations be born female. Though people began to panic, a scientist named Ardat discovered a method known as binary cloning to allow the continuing of her people. Following contact with the Terran Federation, several Eyren began emigrating to Terran Federation space. Many began coupling with humans, discovering them to be very compatible with Eyren for reproduction.