There are none, they're all pretty gay friendly and always have been. Even if they aren't, they would never openly admit they're against the gay community. All female pop stars have a massive gay following. They wouldn't **** that up, if they were to, there goes half of their sales from gay fans.
Kelly Clarkson openly supports Ron Paul, Katy had questionable lyrics, and Kesha didn't give two ***** until a few gay kids killed themselves. I think the question is who is disingenuous (Katy, Kesha, Britney) and who isn't (Gaga, Madonna)?