wow! I'm so glad I checked out this thread and especially to know we're not the only ones that have no plans for children. Neither my husband or I have any interest in having kids, we're both 25 and have been together for almost 7 years, married almost 2. After a year or so of dating, we started talking about it because I had never had any interest in having kids. I knew I was really young then and might change my mind, but that it was a strong possibility that my mind wouldn't change. If I would have found out that he really wanted to, we wouldn't have stayed together. I say his mom has "grandbaby fever", and her idea is that it's just what you do - you grow up, get married, and have kids, not that it is an option. Luckily my mom is cool with whatever we decide. My husband says once his sister has kids that his mom will let off, but I'm not so sure, we'll see.
Zoe'smom, lots of people consider us selfish for the same reason you said but I think it would be selfish for a couple like us TO have children because we're not the ones who really want them.
For sbartels, you'll know when the time comes, I have lots of friends having kids now and they just don't get where we're coming from. I can't tell you from experience, but you seem to know what your priorities are for now, so I'm sure you'll figure it all out! Good luck!