Cade, rank knight captain, is stationed aboard the Prydwen as the vessel's medical officer. He is in charge of administering medical exams to new recruits of the Brotherhood of Steel. All members are required to be medically examined by the doctor annually and report for immediate decontamination after contact with outside lifeforms. He is responsible for monitoring the stability of the soldiers, as they can get mentally distraught after a long and painful mission.
When the Sole Survivor asks Cade if sexual relations with non-human species happen often, he will remark that the Brotherhood finds "that type of behavior absolutely distasteful." Cade does admit, however, that the protagonist would be surprised at how often he hears the patient say 'yes' to that question.
Despite the bigotry held by some members, in one of his terminal entries, Cade mentions treating an engineering scribe for a "sexually-transmitted disease" from a ghoul.
There are no special dialogue options for Cade's questions, even if in-game circumstances lead the answer to change. For example, the Sole Survivor cannot say "yes" to having infectious diseases, even if they have mole rat disease.
The following is based on unverified behind the scenes information and has not been confirmed by canon sources.
In the real United States Military, Doctors are commissioned as officers in order to give them "military authority" over their patients. It is possible that the Brotherhood of Steel still observes this tradition, which would explain why their Chief Medical Officer is a Knight-Captain rather than a Scribe.
Cade will sometimes say "please state the nature of your medical emergency" as a reference to the Emergency Medical Hologram from Star Trek: Voyager played by Robert Picardo, who voices Alan Binet. The voice actor of Cade, Dwight Schultz, made several guest appearances on Star Trek: Voyager.
End of information based on unverified behind the scenes information.