Homosexuality

Homosexual characters are romantically and/or sexually attracted to the same gender. If you want to be less formal, you can call them "gay" or "lesbian" or, y'know, just use their names.

There's a severe shortage of good homosexual characters in fiction; so people who write fanfiction often write a straight character as gay. This can be done well or done badly; and while it's technically an AU, it's usually just called slash, which refers specifically to same-sex romance and is usually the reason someone would write a canonically straight character as gay or bi.

Lots of characters don't have a mentioned sexual orientation; so, just as long as they're kept IC, the writer can take his pick.

List of Gay, Lesbian, & Bi Characters in Fiction
There aren't nearly enough of 'em, but some authors have realized that they don't have to be limited to straight characters and guy/girl pairings.

Literature

 * Dumbledore, Harry Potter (Gay)
 * Vanyel Ashkevron, Valdemar (Gay)
 * Firesong k'Treva, Valdemar (Gay)
 * Daja Kisubo, Lark and Rosethorn from The Circle Universe by Tamora Pierce (Lesbians)
 * Lestat de Lioncourt, Armand, Nicolas de Lenfent, David Talbot and Louis de Pointe du Lac, The Vampire Chronicles (Bi-sexuals)
 * Baron Vladimir Harkonnen, Dune (Gay)

Doctor Who/Torchwood

 * Toshiko Sato (Bisexual)
 * Jack Harkness (Pansexual)
 * John Hart
 * Canton Everett Delaware III (Gay)

Buffy the Vampire Slayer/Angel

 * Buffy Summers (Bisexual, leaning straight)
 * Willow Rosenberg and Tara Maclay (Lesbians)
 * Andrew Wells (Bisexual)

Other

 * Number Six, Battlestar Galactica (Bisexual)
 * Jack Sparrow, Pirates of the Caribbean (Bisexual)
 * Loras Tyrell, Game of Thrones (Gay)
 * Xena and Gabrielle, Xena, Warrior Princess (Bisexual/Lesbian)
 * Zed, Pulp Fiction (Gay)
 * Lexington, Gargoyles (Gay)

Sailor Moon

 * Michiru Kaioh/Sailor Neptune (Lesbian)
 * Haruka Tenoh/Sailor Uranus (Lesbian)
 * Kunzite/Malachite (Gay)

Neon Genesis Evangelion

 * Kaworu Nagisa (Gay)
 * Shinji Ikari (Bisexual)

Other

 * Itsuki, Yu Yu Hakusho (Gay)
 * Jakotsu, Inuyasha (Gay)
 * Motoko Kusanagi, Ghost in the Shell (Gay)
 * Sweden, Axis Powers Hetalia (Gay)
 * Haruhi Suzumiya, The Melencholy of Haruhi Suzumiya (Bisexual)

Video & PC Games

 * Bioware is known for including GLBT characters.
 * Heather, Fire Emblem: Radiant Dawn (Lesbian)
 * Leonardo DaVinci (not the real, historical one), Assassin's Creed II (Gay)
 * Arcade Gannon (Gay) and Veronica Santangelo (Lesbian), Fallout: New Vegas
 * Sims The Sims and any of its sequels can be played as gay, bi, or straight; in TS2 and TS3, they show a preference for the same or opposite gender depending on previous romantic interactions.
 * In the game Fable and its two sequels the player character can be played as gay, straight or bisexual.
 * Kanji Tatsumi (Gay/questioning), Jun Kurosu (Gay), Tatsuya Suo (Bisexual), Persona series

Webcomics & Graphic Novels

 * Wallace Wells (Gay), Ramona Flowers (Bisexual), Kim Pine (Bisexual), Knives Chau (Bisexual), and Roxanne Richter (Lesbian), Scott Pilgrim series
 * The trolls (Pansexual), Dirk Strider (Gay), Homestuck

Miscellaneous

 * Almost everyone in "Rent".
 * Glinda and Elphaba, Wicked (Bisexual)

Related Articles

 * Slash
 * Bad Slash