It has been argued that neurological disorder chorea influenced the choreographic style of the can-can.* It has also been argued that women are emotionally unstable.** I enjoy both of these arguments.
*Nancy Ireson "Dancing in the Asile: Jane Avril and Chorea." In Toulouse-Lautrec and Jane Avril: Beyond the Moulin Rouge. London: Courtauld Gallery in Association with Paul Holberton, 2011.
** Basically everyone.