What has sex got to do with it? Buddha said "there is no difference between men and women." The spirit of transformation is perhaps using sexual transformation to teach that Buddhism's essence is total freedom, regardless of sex.
佛說「分別本無法，無有男女行」，轉身的精神或許在於藉由性別的轉換，教導眾生佛法的真諦是不著色相、非男非女的完全自由。