As long as I'm not paying for them, and they're not being mistreated, it's none of my business how many kids they have. I don't get some of the people on this thread, who have a problem with this. I don't think growing up in a big family, or being "raised" by their older siblings deprives kids, or older siblings taking responsibility for their younger siblings is traumatizing or detrimental for kids. Our grandparents did it, and it didn't do them any harm. Everybody I know from a large family loves being from a large family and having all those brothers and sisters. The only thing that weirds me out about the whole thing is the wetsuits. That's a little extreme, if you ask me.
They might be FreeWill Baptist. I used to work at a Christian camp, and I seem to remember them having similar standards.