For pre-service histories you have a choice between Spacer, Colonist, and Earthborn. The choice that you make here will affect the storyline by accessing specific, exclusive assignments and Shephard's dialogue with various non-playable characters durig the duration of the career.
Likewise, for psychological profiles you have the chioce between Sole Survivor, War Hero, and Ruthless. The chioce made here will affect the dialogue during the story and assignments made available at certain points in your career.
A Spacer, War Hero grants the best paragon bonus. An Earthborn, Ruthless grants the best renegade points. And any other combination of backgrounds grants a neutral point bonus.