As an adult, I have a lot of friends who have 2 kids. I have some friends who have no kids (and who increasingly look like they won't ever have children, since they're my age and older in general). I have a very few friends who have 3 kids. And I don't have any friends near me in age with more than 3 kids (I have significantly older friends who had more than three kids, but those kids are grown now). I'm related to people with more than three kids (duh), and other than those relatives, I do know a few people with more than 3 kids, but not well. Some of this is selection bias. As one of 4 kids, married to someone who was one of 4, and knowing a lot of people who were 1 of 4 or more, I have a theory about 4+ kids that I'm not shy about sharing: if you weren't crazy in _wanting_ 4 kids, you were definitely crazy after you had 4 or more kids. Crazy isn't necessarily bad -- there can be good crazy. But you can see where this would inhibit people with 4+ offspring from wanting to hang out with me. I'm a Bigot on this topic.
I also have friends at the 2 kids point who really want another kid -- at least part of the time. I tell them to Stop Now, because they might get twins. I grew up knowing a family with 3 boys who Really, Really, Really wanted a girl. They got a girl on their fourth try -- along with twin boys. I have never before or since seen such physically attractive, intelligent twin boys so totally ignored. I think their oldest brother mostly raised them. They were terrors, needless to say.
But when I keep seeing people with 5, 6, 7, whatever kids rave about Palin, I gotta wonder: how many of these people are there? Is this normal, and I just don't know about it? I mean, I know the average number of kids per mother these days is below 2 in the US, but that could be a combination of a lot of only children and a few mothers having a half dozen. Where there is google, there is an answer. And the answer is, no, there aren't a lot of mothers out there having a half dozen.
As of June 2006, 17 percent of women 15-44 had one child, 22 percent had two, 11 percent had three, 4 percent had four and 2 percent had five or more.
This doesn't add up to 100% because of things like 15-19 year olds are 93% childless and even women 40-44 are 20% childless (19% in the 35-39 range, which is sort of interesting).
In other words, if there is a demographic that identifies with Palin on the basis of kid-volume, it isn't some mysteriously huge demographic I've somehow avoided running into. The 2 kids phenomena is, indeed, the plurality, and the drop from double digit to single digit occurs at 4 kids.
I didn't read the whole thing, altho I did read large chunks of it. The maps are kind of interesting in a spooky sort of way.