"As soon as you become a licensed professional, you take on certain obligations to act like a professional, which means your patients come first," said R. Alta Charo, a bioethicist and lawyer at the University of Wisconsin at Madison. "You are not supposed to use your professional status as a vehicle for cultural conquest."

Religious objections can be dangerous in emergencies and when health workers refuse to refer patients or inform them about other options, especially in poor or rural areas where there are fewer options.

"It's a very disturbing trend," said Lourdes Rivera of the National Health Law Program, a nonprofit patient advocacy group.

Doctors, nurses and other health-care workers who cannot find a way to fulfill their responsibilities should chose other professions, some say.

"If your religious orientation is such that you can't discharge your professional responsibilities, then you shouldn't take on those responsibilities in the first place," said Ken Kipnis, a philosophy professor at the University of Hawaii at Manoa. "You should find other work."

Others are less sure where to draw the line.