

I take it from this post that by SF you mean only TV? Because there are a lot of gay male characters that are main character in written sf--not 10%, yet, but inclusiveness is far more common than people might think.
Not at all! In fact, several people have sent me some examples of gay male characters in fiction, but few of them are actually the lead. The only two LEADING male characters I've gotten so far are in Dhalgren, and in Jumping Off The Planet by David Gerrold (who is himself gay).
It's harder than you'd think to find one. If you have more examples, please do post them!
There are printed bibliographies; Palumbo is the one most libraries use. On the Web, The Tiptree award and the LAMBDA awards are useful lists: www.tiptree.org/ and www.lambdasf.org/lsf/books/lammys.html. See also the LAMDA Recommended list: www.lambdasf.org/lsf/books/recommend.html. Thomas Disch's works, especially On Wings Of Song. Delany has a number of main characters who are gay; Dahlgren was just an early example of a bisexual main character. See his Stars in my Pocket Like Grains of Sand. See the short stories of Bob Angell. See the Bending The Landscape anthologies edited by Nicola Griffith and Steven Page, and the bibliographies there. There's a panel on queer fic at just about every SF con since the early '80s, and the landscape really is changing--though it seems slow, it's at least moving. It's moving faster in fantasy--see Kushner, Monette, Flewellyn, Elizabeth Lynn, etc.
Awesome, thank you! It's moving a LOT faster in other genres. I pored over the Lambda awards list for many hours yesterday, and was only able to identify a few gay male science fiction characters, but tons in fantasy and horror.