I wrote a very long explanation for why I wouldn't include it.....then SDN froze.
Anywho, here's the short version:
I wouldn't. You shouldn't unless it's pertinent to your ability to be a doctor, which would be very rarely. If you had a leadership role in a group, faced significant discrimination and you can write it into a stellar PS, or other things of the like, then it would be pertinent and you should include it. You shouldn't just say "Guess who has two thumbs and is gay? This guy!!!!"
I imagine it would be uncomfortable for the adcom because they may be afraid you would sue over discrimination if you were rejected even for a valid reason (not saying you would). Also, you don't want to be that person who always talks about just one thing. Everyone knows "that guy" - the person who takes every conversation, regardless of the topic, back to the same fact about themselves. The nontrad in your class who always brings up "well, in the job I had before med school...." ; the person with the mph who asks "well how does this relate to public health" or the person who did a year abroad "well, during my year in London...." I'm not saying you're that guy/girl, you just don't want to come off that way. You don't want to be the person who let's your sexuality be the one thing that defines you and it somehow pops up in every single conversations even when it's entirely unrelated.
Ok, so that wasn't much shorter....but that's my take on the situation. Good luck and try to have some fun for the rest of the year!