Quite a lot. Actors: Neil Patrick Harris, Ian McKellan, Chris Colfer (the Glee kid), Ellen DeGeneres, Jodie Foster, Jane Lynch. Musicians: Elton John, Freddy Mercury, Michael Stipe, Boy George, George Michael, David Bowie (actually bi, not gay), Melissa Etheridge, Rob Halford (of Judas Priest), Adam Lambert, Joe Jackson. TV writers: Ryan Murphy (Glee), Alan Ball (True Blood).

(Started Googling this and realized the list is actually way longer than indicated here - there seem to be more out celebs every day lately.)

No idea if Whitney had anything going on (I actually forgot about the Robin thing until this thread), but if she did that's pretty sad.