My dreams never really focus on gender... So I don't really notice whether or not I'm male or female save for that odd one here or there. I think I've only had two memorable dreams that revolved around gender, actually:
The first dream took place when I was young - around ten or eleven years old. In this dream, I had somehow ended up pregnant. I was absolutely horrified and confused at the idea, so the next morning I made a promise to myself that I'd never get pregnant. So far so good, especially considering the fact that I'm hetero.

The second dream occured shortly after I realized I was trans. In the dream, I was back in middle school, hanging out by the pool with a ton of other guys. Every single one of us was only wearing swim trunks, which was fine with me, but for some reason, I still had breasts. At first, I was embarressed at the idea of walking around without a top on now that I noticed what exactly was underneath, but no one seemed to notice but me, so I eventually got over it. It was nice to be recognized as a guy, despite having been born with the wrong parts.