You can't treat a patient if they're gay?

There's a commercial about to run from the National Organization for Marriage (NOM), talking about the dangers of gay marriage.

In one part, a woman says "I’m a California doctor who must choose between my faith and my job."

I'm still trying to figure out why a "California Doctor" has to choose between their faith and their job if gay marriage is legal.

Do you not treat a patient's broken leg if they got gay married? Or perhaps you're a gynecologist and you determine it's against your faith to give a gay married woman a pap smear? Perhaps a surgeon decides that hey, this gay man with a husband doesn't deserve to have his appendix taken out - obviously it's God's will that they came down with appendicitis.

Seriously here - why would someone either a) being gay, or b) being gay and being married to their partner in any way make a medical professional have to decide between their faith and their job?

"Nurse, fetch me the paddles - this man is in cardiac arrest!"

"Doctor, I can't - he has 'the gay', so it's against my faith to save his life! Jesus would want me to let them die!"

"Oh, well, if that's the reasoning, then I guess OK."

I'm missing something here.