How do you see the phenomenon of male dancers in Kunqu and other operas?

I still understand that there is a historical reason why female roles were played by men, since women were not allowed to perform on stage in the old days. There is also an important reason that the traditional Chinese opera is written, the gender of the characters on the stage and the real gender of the actors can have no relationship, the core is completely in a "performance" word, so not only the male Dan and the female old man. The Dream of the Red Chamber" in the opera house class are girls, but the role played on stage is different men and women of different genders in all walks of life.