Double-Y syndrome (Earth-5875)

Double-Y syndrome is a genetic mutation present in human males in the 26th century. It is a deformation of the X/Y chromosome pair, which results in the YY pattern. The mutation gives the afflicted male a predisposition for violent and antisocial behavior, commonly the rape and murder of women.

Because of the dangerous nature of double-y individuals, they are detained and convicted to penal colonies, deep in the Outer Colonies, separated from other criminals, where they labor for living. Fiorina 161 was one such penal colony, home to the Fiorina 161 Class C Work Correctional Unit and formerly having a carcerary population of five thousand double-y syndrome sufferers.