ואיש אשר יקח את אחותו, when the Torah uses the expression קיחה in connection with someone’s attempt to marry his sister, something outlawed and therefore illegal, legally irrelevant, the word implies that the person to be married is legally free to marry the member of the opposite sex in question. This automatically excludes, gentiles, or the child of a Canaanite slave woman. [perhaps the author felt that the Torah had to repeat the point as, through conversion, such family bonds as had existed had been halachically severed. Ed.]