Colleen McDannell, a professor of religious reports at the University of Utah, informed "20/20" that for Mormons, sex and sexual action outdoors of the bounds of relationship are forbidden. The subsequent marriages of his mom and father yielded four fifty percent-siblings for Gore Vidal - Vance Vidal, Valerie Vidal, Thomas Gore Auchincloss, and Nina Gore Auchincloss - just one action-brother, Hugh D.