What's Up, Doc?

The title Doctor can be confusing in comic books. Whereas Dr. Strange and Dr. Druid both earned medical degrees (Strange was a surgeon and Druid a psychiatrist), that wasn't a given. In the case of Dr. Spectrum of the Squadron Supreme, the hero's alter ego Joseph Ledger was an astronaut with no suggestion that he held the title Doctor out of costume.

In contrast, the Squadron's enemies in the Institute of Evil included Dr. Decibel (a physician). Additionally, the secret identity of Dr. Spectrum from the Squadron Sinister was Dr. Obatu (Iron Man #63), revealed slightly before his first battle against the non-team (Defenders #13-14).

Under the entry for the Squadron Supreme, the original edition of The Official Handbook of the Marvel Universe listed Dr. Spectrum's profession as teacher.