Great comments as I read through them.
As a Dj and dance instructor I gently admonish my dancers that in the Ballroom Dance world there is only a leader, follower and dance etiquette. Here men and women are equal in every way, only they have different jobs to perform and synchronize in order to create great art. Romantic and social traditions fall outside the Ballroom floor and as has already been said, dancers are here to dance, period (and of course make new dancing friends).
While it's true that "outside the floor" tradition says a man should initiate and ask, at the same time it is more common for men to be intimidated with dancing than for women. Yes, we agree that there are more females out there that generally get rhythm, beat and balance, than males. Thus it's quite balanced and again being equal it doesn't and must not matter who asks who to dance. Much more important (I stress this to the guys) is that NO ONE should ever turn anyone down for a first dance request. If you do YOU :( are in violation of Ballroom Etiquette. :)
See ya on the floor...... DjMack