Good thread. I wanted to take a moment to make some comments, since this issue was eventually responsible for destroying a gaming group that I'd been with for over ten years.
First of all, to the parents in this thread...I'm most likely not talking about you. I recognize many of the parents posting here as people who I get along with and agree with on ENWorld, so I'm going to take the bold step and assume you the kind of parents I would love to game with, rather than my unfortunate example from real life. In other words, please don't take any of this personal.
As someone who doesn't have kids, I think bringing them into a game is something that can be (not will be, but can be) problematic and should have a lot of thought behind it. In a nutshell, before you bring gamers into your home with your kids, you should really think about what you're doing.
How is parenting going? If your kids are running you ragged, and you're tired and stressed out, gaming in your home is not going to be a good experience. Gaming requires a lot of time, concentration, and energy ... if you don't have that, it's going to be an awful experience for everyone involved.
Second, how is your relationship with your spouse going? This is important whether or not your spouse plays with you. Realize that gaming in your house, with your kids around, is going to bring to light any issues that may be going on in your relationship, and no one is going to be comfortable with that. If you have problems, work on them (therapy does wonders!) rather than showcasing them for your friends.
Third, after things get started, take a long, critical look at how much gaming you actually get done in the evening. If between dinner and clean ups, bath time, story time, and dealing with child issues time you're getting 30 minutes to an hour's worth of gaming in a four to five hour block, it may be time to rethink the game's location or frequency. In my opinion, no gaming is much better than bad gaming.
Obviously, in the case of my group, all of these things went horribly wrong. My GM was the father, and he had two kids who weren't bad kids in any way, but they were still kids, who needed attention and affection from dad. That combined with the fact that he and his wife (a non gamer) had a rocky relationship to begin with and didn't always use the best parenting techniques, made gaming a horrible experience.
And that leads me to my last point: as a parent, if you're gaming with single or childless people, be mindful of the fact that their time is just as important as yours. For me, I work 50-60 hours a week, and gaming is my relaxation and cooldown time. Coming over to get in an hour's worth of gaming on a good night is a waste of my time, as I could have scheduled something that would have been much more fun and interesting to do for that evening.
I hope none of this comes off as parent or kid hating, because in my case, nothing could be further from the truth. My girlfriend's godson has been a joy in my life: at five he regularly manages to school adults on Carcasson and Apples to Apples, all while being a source of great stories and boundless energy. It's just that not all kids are like that, and making an honest assessment of whether or not you can both parent and game at the same time is critical.
--Steve