So... I was curious has to how players and GMs have incorporated a player character's family into the game, and how they effect the character in question.

For instance, my main's parents are a big part of his backstory, they are slavers who have kids by the dozens for the express purpose of selling them into slavery when they're old enough including him (they evil enough yet?) and this has created an undying hatred of slavery in him. My party eventually raided their compound and captured them, and though we have yet to have the opportunity to do anything about them I have some idea.

In one campaign I play in, my character's long-lost sister was a big part of his backstory, and also his motivation for heading out into the galaxy where typical RPG hijinks ensue. He found her fairly early in the campaign...but her memory was gone. Trying to spark her memory, a really bad roll had her develop a crush on him. A later good roll brought her memory back and ended that particular subplot. Once she was found, she served as a companion character.

In another that I GM, my wife's character has a twin brother. For those of my players who peruse the boards, saying any more would enter into spoiler territory, because they haven't met him yet.

My current players run the gamut from having established zilch-all about their character's family to one who established at least some basics about her adoptive parents and five adoptive brothers. None of them are likely to be the centerpoint of a major plot hook, though we did have a lot of fun when the PCs met her father. Everyone was expecting him to be upset about her becoming a mercenary, but he was actually quite relieved of the news in light of the fact that she'd previously been a swoop racer. "Get shot and you have a decent chance of pulling through, especially if you have a buddy nearby with a stim-pack", he explained. "Smack a wall at a couple hundred miles an hour and it's over ."

One of my players is a falleen merchant, the youngest son of a rich falleen family. His father was an adventurer and made a fortune before stablishing his own business, and told all his sons about how dangerous is the galaxy out there, trying to instill fear on them to not go on adventures. That didn't work for this PC. His brothers and sisters tell about him that is the favourite and spoiled son of his father. And they hate him for that. So they try to ask him favors to put him in danger, or try to sabotage his businesses (and the group's) via third party species.

I normally don't involve family too much in the game unless it becomes part of the story or will introduce a new plot point I want. If my players do not define their past that means it is a blank canvass and I can make it how I want. I will normally introduce them to the family at the end of the session, the player to come up with background for the character and give them guides with what I need them for.

In my current Rebellion game one of the characters was a ex Imperial solider, so I introduce his father who is an Imperial Admiral and a re-occurring villain in the game.

Having a basic framework backstory is helpful for determining character motivations, strengths/weaknesses and whatever else the book wants at character creation and it helpful for the GM to know this stuff - even if it is a single line in a word document per player character. It allows the GM to create events that actually require you to really think "What would my character do in this situation?" Family is a particularly powerful extension to this, particularly if the family life was not the greatest. But then again remember that the Star Wars galaxy is actually pretty far beyond comprehension in scale: all the material, canon and EU, for perspective, would only cover a fraction of a hundredth of a thousandth of a percent. The minute you leave your home-world and stop sending email to your family, chances are you are never, ever going to encounter them again, particularly if you are a human (the human population of the galaxy is measured in the tens of trillions). It is similar for most non-humans save those that never really left their home planets in any meaningful number.

And it gets worse when you realize that not only are you mobile but the rest of your family is as well. While your parents may stay in their home, if you left, chances are that your siblings did too. It is trying to find a needle in a haystack of practically infinite size. Knowing this you could probably toss familial relations out unless they are actively in contact, which I imagine most wouldn't be, particularly if you have a particularly nomadic lifestyle (smugglers, freighter and naval crews, etc).

That being said in the games I have GM'd I have seen/implemented the following, usually using obligation or morality (or combination of thereof):

• A Shistavanen who was exiled from his tribe by his younger brother who usurped the chieftanship from him. Not confident in his position as Chief, he occasionally sent out hitmen ranging from clan loyalists to bounty hunters to kill him until he made the choice to return home and bring a definite end to the issue.
• An Arkanian student who send his mother biological samples from his travels to further the never-ending pursuit of genetic perfection.
• A Togruta who was determined to get revenge on her family for selling her into slavery to pay off their debts.

None of the other players I've run sessions for have brought their family into the equation.

My current character has a set of adopted parents who found him as an egg, (he is a clawdite so I made some logic leaps. They are some of the best engineers on Naboo and currently have a target on their backs by the hutt who found out my character is a clawdite. Hopefully the hutt doesn’t find out that he is also force sensitive anytime soon.

One character I played was Ping Krell, a Besalisk Heavy Weapons specialist. He is distantly related to Pong Krell, but doesn’t know much about his uncle, only that he died in the Clone Wars.

In my current campaign, we are set during the Clone Wars, so as a Jedi, Markus doesn’t really know much about his birth family. I’ve always had a certain backstory in mind that wound up with him landing in an orphanage on a planet like Jakku, and someone like the Guardians of the Whills noticed that he was always preternaturally prepared for just about everything that was about to happen, like he was expecting it somehow. So, word got out to the Jedi, and when they arrived he was already packed and the headmaster had been informed in advance of who would be arriving, when, and what would happen. The door wasn’t open for long, and they were glad to be rid of him.

For other characters I’ve played, family history and family members weren’t really a factor.