There have been studies which suggest that more gender-transgressive queer people run a greater risk of queer-bashing. And certainly these types of visible gender transgressions have long been associated with queer people.

However, I also think that the act of same-sex sexuality is itself also seen as transgressing outside one's proper gender sphere. That is, I think that in the U.S., "proper" gender expression is heterosexual. For example, one can be a very femme woman -- dress, makeup, body discipline -- but as long as one is still sleeping with other women, one is not performing femininity "properly" according to Western gender norms.