The website of the Cancer Treatment Centers of America giove the names of various medical pratitioners, along with their bios. All pratitioners with doctoral degrees (M.D.'s, O.D.'s, Ph.D.'s) are referred to as "Dr." except the N.D.'s, even the ones who are licensed in their state of practice. All N.D.'s are referred to by their first or last names - not Mr., Ms., or Dr. Why? Bias or ignorance?