I have no problem with Ph.D. holders using their credentials when they are speaking outside of health care and biology. Within those topics, however, it is a major ethical faux pas to omit a completely irrelevant doctorate. Either don’t advertise the credentials in the first place, or don’t speak on medicine or biology without coming clean. And yet I know an influential individual who does precisely the wrong thing with this. He is a constant reminder to me of just how easily people can deceive themselves and others.