First off - I am of the mindset that it is there own business. Personally I think it is C-R-A-Z-Y! I want a large family by today's standards, but 18 is just WAY too many (for me at least). I have watched all of their cable specials (it is hard not to) and I seriously think they get state or church help cause she is a SAHM/home schooler and her DH isn't a state rep or whatever anymore. They just built a huge house - their master bedroom has a dedicated nursery nook
Oh, and they do the buddy system. When Mom has a new baby, the next older kiddo in line gets the youngest to be their "buddy" so they help them get dressed, brush their teeth, etc.