I work with what the players give me.
In my current campaign, I have a character that has a strong, loving relatioship with her family. She followed one of her older brothers into the adventuring life, had some good luck (C'mon the characters are the hero's, not the character's families!), and now she tries not to overshadow him too much. There is a little envy, but it is a strong family.
I have another character that came from the "abusive household". She lusted for power and eventually gave in. We played it up for a short time until she could split the party without being pursued.
I have yet another character that wrote his history to include avenging his father's death and then splitting town before anyone figure out who was responsible. He left behind his brother and sister, whom he cares for a great deal.
The sorceror left home, but has been back to visit. Most of the party has met his mother.
The party's paladin has a step-sister that got older and parted ways. Their parents were killed by goblins. When he started adventuring, one of his goals was to find his sister. Eventually, he did, just not quite the way he expected. She was one of the stabilizing forces in the personality of an NPC that was afflicted with magical Multiple-Personality-Disorder. She helped influence the Good personality.
Admittedly, this NPC is the sister of the Cleric. His family was cursed to betray their god. Very convoluted storyline! It is alos the only example of me taking the character's background and "screwing with it". Although, at the time, the character didn't know his sister was alive. After all, she disappeared in a goblin attack when he was 3. She was a major NPC and they eventually saved her. The Paladin and the Cleric were a bit surprised to find out that their sisters knew each other, it is sometimes a small world.
I encourage my players to have family, if it fits in with their character concept. I won't try to use it to screw them over, but I reserve the right to use it for plot hooks!
