Halfbreeds were persecuted mixed-race Orions, crosses between the Green Orions, the Ruddy Orions and the Grey Orions. Interbreeding between the subraces was feasible, but difficult; most had life-spans of only a few months. Ruddy–Green crosses were the most likely, given the numbers and health of each. Ruddy–Grey and Green–Grey were theoretically possible, but none were known to exist. The mutilated genetic code of the Greys meant that survival was highly unlikely—a hybrid birth would require intensive medical care, only found inside a guldin, a Grey Orion life-support chamber. A pregnant non-Grey would never be allowed out again.