Dear Tomdstone,
Good question. I think there are a couple of issues here.
There is a family at the local SSPX Church with 15 children. The mother looks very tired and she is pregnant again. I know that artificial birth control is a mortal sin, but are there exceptions?
First of all, I think the term “artificial birth control” confuses things a little. The issue does not hinge on whether the acts in question are aided by a man-made device or not, but on whether or not they deliberately impede conception. I prefer to call it “contraception” (without qualifying it).
In any case, contraception is intrinsically immoral (see the
number 2370*Catechism * for a definition), and hence there are no exceptions.
I mean, suppose that the doctor advised her not to have any more children because of health reasons, and he prescribed a contraceptive pill. Further, suppose that the rhythym method or NFP does not work for her. Would it be a mortal sin for her to have this prescription filled and use ABC in order to preserve her health and be able to take care of her 15 children? It seems somewhat harsh to send such a person to eternal damnation in hell after she has raised 15 children and done her best for her family and her children.
That doctor would be in his rights to advise her not to have any more children, but he should direct her to use methods that are morally OK. We should keep in mind that natural family planning does not use the “rhythm method,” but instead takes advantage of the latest advances in science to help couples know when the woman is fertile. This knowledge can be used either to prevent pregnancy or to foster it.
In fact, a couple that carefully and conscientiously applies natural family planning in order to prevent pregnancy has a lower chance of pregnancy than one relying on chemical or physical contraceptives. (I usually explain it as follows: if you use contraceptives, you are relying on the
pill to keep you from being pregnant; if you use natural family planning,
you get to decide if you want to be pregnant or not.)
(Have a look at
thebillingsovulationmethod.org/ or
creightonmodel.com/ for for information on NFP.)
The problem does not lie in limiting the number of births, per se, but in the means applied to do so.
After all, how many Catholic families have only two children? Why condemn such a person as this saintly lady if she decides that 15 children is as much as she can handle and she follows the advice of her doctor.
As far as the state of the soul of the person in question, there is no question of condemning anyone

. What a person may subjectively decide to do is between him and God.
Remember, contraception hurts the persons who practice it; it is particularly dangerous for the health of marriages. The Church teaches what she does to avoid trouble for all concerned.
(Natural family planning, incidentally, is in general extremely helpful for fostering communication in a couple.)
Hope that answers your question! God bless.
Father Louis Melahn, L.C.