Yes. I am a woman and I have had dreams in which I am the opposite sex.
The first time, or rather times, it was in a series of dreams where I was two people at once, experiencing the dream from both perspectives at thesame time, although within the dreams neither one of my selves were really aware of the perspective of the other. This was when I was about fifteen in real life, and one of my dream selves was the same. The other was a Vietnamese boy who could be anywhere from six to twelve, and while the rest of the details are now blurry, there is the definite knowledge that came with the dream that he was from Saigon, rather than Ho Chi Mihn city. (I will add that at 14 and 15 I was very...poorly informed of politics and knew very little about the Vietnam war or the significance of Ho Chi Mihn city vs. Saigon).
The second time I remember was a few years ago. I actually don't recall if I really became the opposite sex or if people were just mistaking my identity. This may require just the briefest bit of political background--without getting bogged down in the details I am....not particularly fond of the current president. I would like to see him OUT of the presidency. Now on to the dream. I was on a train. People were mistaking me for him. So, in an attempt to undermine him I started saying various...politically incorect things. I figured if people thought I was him, I might as well make him look bad before I quietly left the premises. Well, there were media reporters there, they were tryiong to ask questions to guide me back into more politically correct realms. They clearly were going to ignore everything bad I was saying.
Went on to explore the train. The men and women were segregated. The top level of the train was devoted to the elderly. One poor old man was trying to navigate his way up a set of stairs to that level, and just couldn't make it. I remember thinking what a stupid plan that was to put the elderly at the top where they had to go up flights of steps.
Eventually people started screaming and the train derailed, I wandered off, was myself again (or maybe I always was and it was just the others mistaking me for someone else), and I wandered off before anyone could find me and get me in trouble.
Finally, just a few days ago, I dreamed I was Harry Potter. At the Dursleys, held captive in my room /Harry Potter's room (If you haven't read the books or seen the movies, you probably need to to understand the context...). I had my tongue pierced, which was attached to a chain coming from my mouth. At some point in the dream it got caught in someone's hair, blech, and it hurt, too.
There were a bunch of people from Hogwarts in my room. Vernon Dursley didn't like this, but making the best (in his mind) of what to him would be a bad situation, he started giving my (Harry Potter's) stuff away to the students that were present, who were very reluctant to take it. I remember he was trying to get one kid to take it (the kid was in at least one of the movies but I can't remember which one). I remember saying something along the lines of "Just take it, if you don't he'll just try to give it away to someone else later, at least I know you'll value and take care of it." Dream ended at some point after that.
Just thought I'd share....