A coworker recently filed a claim on behalf of a young woman, and asked her relationship to the cardholder on her insurance, since it was also a woman's name and she was >25. The woman excitedly stated, "She's my partner!" My coworker looked surprised (gay marriage is fairly new to IL). I thought she might be uncomfortable, so I made a joke with her when the patient had left, "You need to clarify with her, you should ask if one of them plays the guy's role."
I have a twisted sense of humor and enjoy off-color jokes; everyone who I work with knows this about me. But instead of laughing, she gave me a dirty look and said, "Zanick, did you know that my mother is gay? She married a woman two months ago." I tried to play it off like it was no biggie by pretending like I'd done nothing wrong: I said, "Really? That's wonderful, I have a lot of respect for the gay community!" plus my usual liberal shit, and we ended up having a nice talk about the political nature of the subject.
I'm sure she was deeply offended at first, and I'm hoping I haven't damaged our professional relationship because we work closely and have always gotten along otherwise. So far I think she just wrote it off as ignorance and bad humor, since our manager hasn't approached me about it at all.