A ten year old girl is married to a 70 year old man. Is this rape? In this country, yes, but in other countries, no. And even *within* countries – some states have age of consent for marriage at 14 (with parental approval), others 18 with no exceptions.
Cultural relativism states that a person's beliefs, values, and practices should be understood based on that person's own culture, rather than be judged against the criteria of another. But does something cease to be wrong simply because of tradition? Wasn't that the point of Shirley Jackson's short story "The Lottery"? Is there a universal ethics boundary that cultural relativism can't cross?