OK. It is somewhere in that ballpark, and, of course, there is a point when NFP to avoid pregnancy becomes allowable, even though it is not yet virtuous (it becomes virtuous, for sure, if that extra child puts the couple on welfare). A couple that feels it has "met the obligations of social justice" should examine their conscience with a priest before they can embark on pregancy-avoidance with NFP. I would caution the reader against an impression that God sets any kind of procreation quota, from your post, or that social justice can overrule the procreative activity of God, but I would not have a drawn-out discussion over it.
Hemann: "If one has met the obligations of social justice to provide posterity, it is perfectly licit to avoid having additional children to afford material things."
What does God have to say??
Genesis 1:22
And God blessed them, saying, "Be fruitful and multiply, and fill the waters in the seas, and let birds multiply on the earth."
Genesis 1:28
Then God blessed them, and God said to them, "Be fruitful and multiply; fill the earth and subdue it; have dominion over the fish of the sea, over the birds of the air, and over every living thing that moves on the earth."
Genesis 9:1
So God blessed Noah and his sons, and said to them: "Be fruitful and multiply, and fill the earth.
Genesis 9:7
And as for you, be fruitful and multiply; Bring forth abundantly in the earth And multiply in it."
Genesis 35:11
Also God said to him: "I am God Almighty. Be fruitful and multiply; a nation and a company of nations shall proceed from you, and kings shall come from your body.
Etc., etc.,etc.
I have trouble seeing how avoiding children fulfills this command. Does God not open and close the womb? Is it excusable to disobey God's command in order to avoid going on welfare?? In God's view there is no such thing as "licit" or "illicit". There is only obediance or disobediance. God cares nothing about the laws of man, only His own Holy and loving commands.
BTW, I notice Biblical evidence is very sparse on this thread. Much opinion but little evidence...