Soldiers with Gene Mods can undergo psionic testing and the genetic modifications stack with psi abilities. Gene Mods can be administered to any soldier except MEC Troopers. Soldiers are removed from active duty for three days for each Gene Mod applied. Gene Mods are applied at the Genetics Lab, which can modify up to three soldiers at a time. Using Meld to organically fuse elements of alien genetic adaptions into a soldier's body, Gene Mods grant the individual new super- human capabilities. Performing alien autopsies can result in access to new genetic modifications. They modify a variety of human anatomical systems, yielding different tactical advantages. Up to five genetic modifications may be applied to a single soldier.