Early attempts to create alien-human hybrids were pioneered by German and Japanese scientists shortly after World War II , and for some time during the Cold War . However , these often met with failure , and the Syndicate started to rely more on their own scientists . According to the Alien Bounty Hunter , in the 1950s , Soviet geneticists found a unique genetic anomaly within identical twins . The Colonists and Syndicate scientists used this to eventually develop human clones with alien elements and partial hybrids , but they were still ultimately inferior . Hybrids of this type include Samantha Mulder , Kurt Crawford , the Gregors , Ernest Calderon , and Dr. William Secare . Child and adult versions of Samantha and Kurt are also seen . These clones have the same caustic greenish blood of the aliens , have greater muscular strength and higher physical endurance levels than most normal humans , and can breathe underwater . In addition to their intended use by the alien colonists , the Syndicate is occasionally seen using these clones to perform various tasks , such as research and physical labor
Japanese scientists
Unit 731
Colonist (The X-Files)