Should there be a limit on how many children you can have?

At what point should someone step in and cap the number of children you can have?  Is America overpopulated?  Should you have to have a license to parent?

Josh Duggar, the eldest child of the Duggar clan, and his wife, Anna, are expecting their second child this summer.  To me the Duggar family has way too many children.  My fear is that the children are getting neglected.  I don't think it's fair the older children have to take care of the younger children.  They are robbing the older children of their childhood.  I just don't see how the mom and dad can give each of those children enough time and attention.  What do you think?