I bring up the question because, in my experience, relatives are not common aspects of a game. ESPECIALLY not core aspects of a game, like the main character's father in Fallout 3 was-as you had to find him for a good portion of it. Unless you took short cuts. ;] Usually if there ARE relatives, they're just "there." Or, worst yet, they were just "there." As in before you had any part in the game, at all. This is especially common if you have some sort of special ability or position in being related to them, often the case for the role of the "chosen one"-and I don't mean just the character from Fallout 2.
I personally thought the whole concept of actually having relatives, and people attached to your childhood, was pretty awesome. But like a lot of things in Fallout 3 when it comes to characters, I felt they didn't fully utilize the concept's potential. Especially when it came to making those characters likable and with thorough depth. Especially with characters like Amata, who was supposed to be your best friend, but seen as annoying or worse by most people. Even I often found she seemed to be more of a best friend when you weren't there than when you were. Though, I'll give Bethesda credit for not having the father, James, simply found dead. I was expecting such, for the very reason of a lack of relatives in my experience of games.