I can just see it now..."temporary guest worker program" for
"X" number of months/years...whatever...then "POP"...OOPS! Oh look at that...a baby!

"Now how can we send the parents back to their country and leave that poor "American born child", in this country without any parents!? How inhumane! So, we have no choice but to make the child's parent's legal citizens. After all, we are only doing this for the child's well being, you know!"