Almost all my friends have kids.
Though I have a few friends back on the east coast with whom I'm close who don't have children, most everyone else I am in contact with has at least one child. Being a military wife, lots of women I'm around are spitting out babies like it was as simple as baking cookies, and an absolute duty. Get pregnant, husband deploys, have baby, husband comes home, rinse, repeat.
I do have friends who have only one child though, and others with fertility issues who are either immersed in work or baby-sitting to try to help shake the baby urges.
It can certainly be difficult for those of us who don't have children (who want them) on a military base, especially at neighborhood functions, the grocery store, y'know... everywhere.
One thing that is interesting about having friends from all over the country who have children, I have been exposed to all sorts of different parenting styles. Seeing the differences and correlations and the effects on the children is certainly an interesting practice.
I was raised in backwoods VA where spanking or 'switching' was the norm. A kid getting knocked on the butt with a frying pan wouldn't have been abuse, it would've been called discipline. I've seen mothers who can't even say 'no' to their kids. Everything in between. Seeing so many parents will definitely affect my parenting techniques in the future.