The Crawford hybrids (played by David Lovgren and by the Casey and Sean Murphy twins as children) were a series of hybrid clones produced from female abductees' ova. They were employed by the Syndicate in the colonization project. The individual they were cloned after is unknown, but it is possible he was the son of a Syndicate member. Kurt Crawford was the name of one man in the Crawford series, but since the rest of them are not named, this name is also used as a reference to the whole group, similarly to the Gregor or Samantha Series.