I bolded the part I wanted to address ... I have no doubt that they are indeed raising their own kids. I grew up in a religious background similar to the Duggars in that birth control was a no-no and families routinely had over a dozen kids. There are a few my age who, while they haven't taken it to the level of their parents and grandparents, still have 8, 9, or 10 kids. Believe me, in each of those families, the parents are the final authority on everything. They set the tone for the home; they are in charge of emotional, spiritual and educational growth. The older kids do indeed do chores and assist with the smaller ones, but they are not any type of authority to the littler ones. And while they might seem odd to outsiders, I don't know any of them that aren't loving, supportive, nurturing environments. From what I've seen of the Duggars, they have the same type of relationship with their kids.
As long as these families are turning out upstanding contributing members of society (doctors, lawyers, engineers -- yes, even the girls! -- they're not out to oppress their females) I can't hate on them for choosing to have a ton of kids, just like I'm sure they wouldn't hate on me for choosing to have only one.