Superhuman abilities may result from human enhancement by cybernetic implants developed by Microsoft.
 However, only half of the human population can actually tolerate promicin, and thus develop superhuman abilities, while the other half die upon taking the shot
 While the offspring of a returnee normally do not retain the ability to generate promicin, a second-hand report from John Shaffner (an ex-special ops soldier) suggested that the offspring of a 4400 and a Starzl mutant will be "promicin-positive", meaning they will have abilities

