COLORADO CITY, Ariz. - In a dusty neighborhood under sheer sandstone cliffs studded with juniper on the Arizona-Utah border, a rare genetic disorder is spreading through polygamous families on a wave of inbreeding.

As a German brother and sister take their fight for the right to a sexual relationship to the country's highest court, the BBC News website's Clare Murphy looks at the history of the incest taboo and how it is changing ( Read more... )