Vittoria Tesi, a famous singer in the 18th century, refused to play pants roles because it was "harmful to her health." What does that even mean?
Maria Cere was considered so ugly that she was never allowed to take female roles. Therefore, she "specialized" in pants roles. What a compliment.
Metastasio's libretto "Achille in Sciro" tells the story of Achilles who's dressed as a woman until the end of the night where he throws off his trappings and reveals his true gender. However, the part of Achilles was played by a woman at the premiere. Strange, much?