I read that some Quiverfull adherents believe that they are building an army of conservative Christians for God, the movement as a whole is anti-feminist and encourages a patriarchal system, and that it originated in part as a backlash against the feminist movement and growing acceptance of birth control within American Christianity. Not every couple who have many children and/or as many as they physically can identifies as being members of Quiverfull, but I think there's more to Quiverfull than just having a lot of children.