Reasons for Natural Family Planning
by Msgr. William B. Smith
Published in Homiletic & Pastoral Review (February
Question: How “serious” are the “serious reasons” for
practicing Natural Family Planning? Some call NFP Catholic contraception;
others say the opposite. What official teaching answers this directly?
Answer: First, NFP is not any kind of contraception
when we understand that term to be “artificial contraception.” Some style themselves “Providentialists” in
their claim that God will provide for whatever number of children you have.
Of course, married couples (and all Christians) should trust in divine providence.
But, as G. Grisez points out: “But providence has given the Christian
couple reason enlightened by faith and the power to act in accord with it” (Living
A Christian Life, v.2  p. 682). Piety should not be confused with
As for the “serious” or “just” reasons, more, I think,
can be said about their generic kind than about their specific weight in
a given case or life.
The classic encyclical, Casti Connubii (1930) of Pope Pius XI does not
mention this precise point but speaks only of “virtuous continence which Christian
law permits in matrimony when both parties consent” (CC, par. 53;
It was, rather, Pope Pius XII in his famous and extensive “Address to
the Midwives” (Oct. 29, 1951) who first spoke of a positive obligation
for transmitting life but as a positive obligation it can admit of excusing
causes, i.e., “grave motives” independent of the good will of those
obliged. These “serious motives” he categorizes as four kinds: “medical,
eugenic, economic and social” (AAS 43  p. 846). These can
exempt from this positive duty for a long time, even for the entire duration
of the marriage.
Thus, according to Pius XII, the choice to avoid or postpone birth can
be licit under just and reasonable conditions. But, without serious
or just reasons of this kind the deliberate will to avoid the fertility
of this union must derive from a false appreciation of life or motives
foreign to right ethical norms. (For a close commentary on this teaching,
cf. Ford-Kelly, Contemporary Moral Theology, v.2  396-430).
Next, the ex professo treatment of marriage in Vatican Council II (Gaudium
et Spes, nn. 47-52) is both helpful and pertinent to this question.
The Council teaches: “Marriage and married love are by nature ordered to the procreation
and education of children. Indeed, children are really the supreme gift of
marriage and contribute very substantially to the welfare of their parents” (GS,
Within that context which will shape and form the new Code (cn. 1055,
#1) and the new Catechism (#1601), the Council mentions factors
couples should consider: their own welfare and their children (already
born or foreseen); material and spiritual conditions of the times and
state in life; and even the interests of the family group, temporal
society and the Church itself (GS, 50).
The Council then teaches: “The parents themselves should ultimately make
this judgment, in the sight of God” (GS, 50). This cannot
be an arbitrary decision but a conscience judgment conformed
to divine law and Church teaching which authentically interprets
that law in light of the gospel (GS, 50).
Lastly, in harmonizing conjugal love with respect for human life,
the Council taught that the moral aspect of choices here “does not depend solely
on sincere intentions (motives only),” but on objective standards “based
on the nature of the human person and his acts that preserve the full sense
of mutual self-giving and human procreation in the context of true love” (GS,
Next, Pope Paul VI in Humanae Vitae (1968) nn. 10 and 16 continues
the same teaching of Pius XII and the Council. The Pope teaches: “In relation
to the physical, psychological, economic and social conditions, responsible
parenthood is exercised either by a deliberate and generous decision to raise
a numerous family, or by the decision, made for grave motives and with due
respect for the moral law, to avoid for the time being, or even an indeterminate
period, a new birth” (HV, 10).
Two small points here. The “eugenic” reference of Pope Pius XII
has been replaced by the “psychological” reference of Paul VI.
And Humanae Vitae speaks of an “indeterminate time” instead of “for
the entire duration of the marriage.”
Curiously, in the magisterial exhortation of John Paul
II, Familiaris Consortio (Nov. 22, 1981)—a document many times longer and larger than Humanae
Vitae—there is no mention of the “reasons” for
practicing NFP where you would surely expect it.
However, the same Pope, John Paul II, in a book-length
series of talks, Reflections on Humanae Vitae (1984) does
address this question specifically (General Audience, Sept.
5, 1984): “Responsible Parenthood Linked to Moral Maturity.” He
notes that NFP can be an abuse if used for “unworthy reasons.” And
that a morally correct standard takes into account
not only the good of the family, but the health and
means of the couple, along with the good of society
and the Church. (This repeats the factors mentioned in GS, n.50).
Lastly, in his encyclical, Evangelium Vitae (March
25, 1995), in Part IV building up a new “Culture of Life,” John Paul speaks of the work of education,
training couples in responsible procreation: “This happens when the family
is generously open to new lives, and when couples maintain an attitude of openness
and service to life, even if, for serious reasons and in respect for the moral
law, they choose to avoid a new birth for the time being or indefinitely” (EV,
n. 97). (Both in Latin and in translation, this is verbatim HV, n.
Where does this leave the question? I think J. F.
Kippley is correct when he writes: “You cannot decide for anybody else what generosity means in
their case” (Sex and the Marriage Covenant  p. 205).
The providentialists say do nothing to interfere
with procreation (including NFP). The seculars say
have 1.78 children. The Catholic position is neither
of these but calls for generosity, while recognizing
serious reasons in some cases call for more spacing
and family limitation. The point is to get the couples
to ask themselves are they really answering God’s call to generosity
in the service of life. Kippley is correct—a
good place to start is to read reflectively GS,
nn. 50 and 51.
Another helpful source is Christopher West’s Good News About Sex and
(rev. 2004) chapter 6, pp.107-133,
and for this precise question #12, pp. 118-120.
Published in 2005