I've noticed that in recent years that physician listings in telephone yellow page directories break down doctors in gorups of MDs, DO's, DPM's, DC's, etc. I seem to remember a time when MD's and DO's were all listed under "Physicians and Surgeons". I don't think this is necessarily bad but I have noticed in a couple of cities several M.D's are listed in the D.O. section. I've tried to call a couple of those listed to inquire why but haven't been able to get past their receptionist. It's not an earth shaking question or concern, just curious. Any insights?