Always been encouraged.
I grew up living with my grandparents and I was encouraged from a very early age to do anything that involved reading and writing. This was later expanded to include computers and photograpy.
In 1980 (5th grade) I had the opportunity to enter the gifted program that our school district had put in place. This involved transferring to a different school across town.
I didn't know anybody at the school (no one else made it in to the program from my school) but I easily made friends with a group of guys who were all learning to play D&D (blue book at that time, and then 1E later on).
I was also exposed to Star Fleet Battles, Top Secret, and a variety of other games. I spent many hours reading these game books as I made the hour long bus trip to and from school.
We were kept segregated from the general population of the school (different lunches and recesses) and this really helped to fuel our interest in gaming. You can't really play kickball, football, or soccer when you only have 5 people who want to play. D&D and the like are, obviously, an entirely different matter.
My 6th grade final project involved writing a book report, and designing a wargame, about the battle of Midway Island. The book report and game were both a success.
During my junior high years I didn't really game much. I became heavily involved with comic books (reading and collecting) and developed a minor interest in playing football. The interest in football continued on into high school, but eventually lost out to gaming when I had to decide which activity to attend.
When I entered high school I was re-united with a couple of my friends from grade school and we began gaming again. We approached our English/History teacher about being our Gaming Club sponsor, and he accepted (a BIG thanks to Mr. Martin in the unlikely event that he is reading this!). We would spend every day after school gaming until the custodian would come in and kick us out, which would usually be around 5:30pm.
My grandparents have always supported my interest (both emotionally and financially) in doing anything that involved learning, creativity, and imagination. This support has now been passed on to my children, and my nieces and nephews. I never realized how spoiled I was until my wife and I compared our lives growing up.
My grandma once said this about gaming.. "We know where you are. We know you aren't taking drugs or drinking, and we know you aren't getting anybody pregnant. That's a lot better than a lot of kids these days." And it was all true. I think my interest in gaming and the support that I received at home helped me to avoid a lot of the problems that teens usually face.
My wife is a casual gamer. She'll play Dungeon and a few other games, but isn't really interested in role-playing. She thinks that we spend too much time "talking" and not enough time "killing stuff". I'm not sure how I feel about this!
My oldest daughter (10 years old) really likes to play Dungeon and may eventually want to learn how to play some of the other games. I'll leave that up to her.
My younger children (4 and 5) really like to help me roll the dice when we play. They'll often sit on my lap and eat my snacks as well.
The in-laws don't seem to have any problems with it. I've always said that it is secondary to family and marriage, and act accordingly.