Posted: Tue May 02, 2006 11:34 am
Interesting question. I'm not sure if siblings mated there would be any strange consequences. With some other animals, it can cause congenital weakness (I've read there's currently controversy over breeding race horses this way). If you mean species in-breeding, however, some subspecies can mate (i.e. RES and YBS). This is not generally encouraged, however, and the resulting hybrid, I've read, would be unable to reproduce.
"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-