As you can see, Dr. Fate's doctor title comes into question by Harley Quinn. I see this on Twitter all the time and being an over obsessive nerd, it tends to irk me. Mostly because people are wrong. Many who have held the Helm were actual doctors. Two of which were M.D.'s. I'll give Tom Taylor that this is an alternate universe and who knows what this Dr. Fate has accomplished as a civilian, in fact we are not even sure that it is Kent Nelson under the Helm. But let's look at the evidence, the original, Golden Age Dr. Fate eventually went back to school to become an actual physician. As seen in the panel below:
If you want to dismiss this as Golden Age silliness, Dr. Fate actually references his training a few times in the Silver Age when he was part of the All-Star Squadron. If you want to dismiss this altogether, he has also referenced a PhD in Archaeology when Inza took over as Dr. Fate.
Kent Nelson's Grand Nephew, Kent V. Nelson, who was the last to wear the Helm before the New 52 came into being, was a licenced Psychiatrist. A psychiatrist differs from a psychologist in that a psychiatrist is an M.D. not a PhD. and is able to prescribe medications.
Lastly, the New 52 Dr. Fate (Khalid Ben-Hassin) also holds a PhD. in Archaeology. True he is not THAT kind of doctor, but a doctor none the less.
Lastly, there have been several instances in which Dr. Fate has used his powers either to heal someone or at the very least keep them alive. So if a doctor is defined as someone that heals, Dr. Fate is definitely a doctor.