Dr. Richards served the NCR as a medic during the first Hoover Dam assault. He originally joined the NCR military because he believed in the ideals that the NCR stood for, and wished to use his knowledge to help others. After seeing so many other soldiers die, however, he lost his sense of idealism and just wishes for the fighting to end.
If one has the Confirmed Bachelor perk, Dr. Richards will address the player as "little buttercup", "[my] fine dear", say "I'm always a sucker for a pretty face" or exclaim that the room just got a little bit hotter, indicating that he's homosexual. This is proven if the player has the Wild Wasteland perk with which a name in the credits says "Dr. Richards is a dude, and he likes dudes".