Man, I hate it when people answer "homosexuality is wrong" with "homosexuality isn't a choice." I believe that that's true--hell, if it were a choice, there are millions of people who could make their lives a whole lot easier and safer by simply choosing the opposite sex--but on another level, I believe it shouldn't matter. I want to be able to answer, "if being gay was a choice, it still wouldn't be wrong."
Likewise, I hate it when people answer "Plan B is wrong" with "but what about rape or broken condoms?" I want to be able to answer "No, no it's not. Even if I was sober and consenting and just plum decided to have unprotected sex, it wasn't wrong. I may be stupid, but I'm not wrong."
Don't make excuses for something you don't need to apologize for.