Licit Forms of Natural Family Planning

Posted: January 28, 2012
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No Reason to Reject Standard Days Method

WASHINGTON, D.C., JAN. 25, 2012 (Zenit.org ).- Here is a question on bioethics asked by a ZENIT reader and answered by the fellows of the Culture of Life Foundation.

Q: The Standard Days Method (SDM) of Natural Family Planning (NFP) was introduced by Georgetown University and uses a bead counting method. Some Catholic doctors and priests have criticized the SDM for some/all of the following reasons:

1. It is not natural because a computer model was used to calculate the days of abstinence.

2. It is endorsed by USAID (which has links to abortion funding).

3. The original research paper left open the possibility of using a back-up method during the fertile period.

My question is: Can Catholic licitly teach and practice the SDM? -- Fr. JM, Southeast Asia

E. Christian Brugger offers the following response:

The Standard Days Method of fertility awareness is a newer and more precise variation of the older calendar (rhythm) method that used the length of a woman's menstrual cycle to estimate when fertility was most likely to occur.

Promoters of the SDM state that the newer method is only reliable for women whose cycles range in length from 26 to 32 days. Women outside this range are encouraged to use another method. Those who fall into that range and who wish to avoid pregnancy are advised to abstain from intercourse on days 8-19 of their cycle. These are the days, according to the method, when they are most likely to conceive. SDM literature reports that when the method is used correctly it has a 95% rate of effectivity.


This is not so different from the older calendar rhythm method whose rate of effectivity, when used correctly, was 91%. The problem with the older method was that couples were required to carry out mathematical calculations that the SDM has built into its approach. So whereas the perfect use failure rate of the older method was 9% (91% success rate), few couples used it perfectly. The actual use failure rate, because of the method's complexity, turned out to be 25%, which meant that couples trying to avoid pregnancy got pregnant approximately one in four times.

From the user's perspective, the SDM is much simpler. As stated above, it is limited to women with a specific and reliable cycle length. Once that is established, the days on which couples are advised to abstain are easy to determine. In some countries, a simple string of beads is used to assist women to count off the days of abstinence.

As for its ethical analysis, the SDM is simply a method of NFPassisting couples to regulate their fertility in ways consistent with the natural cycles of a woman's body and with moral norms taught and defended by the Catholic Church. Other methods include the Billings Ovulation Method, the Sympto-Thermal Method, the Creighton Fertility-Care Method, and Ecological Breastfeeding.

In the 1930s, the Catholic Church judged that NFP was a legitimate way for couples to regulate births. Pope Pius XI taught in Casti Connubii (1930): Nor are those considered as acting against nature who in the married state use their right in the proper manner although on account of natural reasons either of time or of certain defects, new life cannot be brought forth; and two years later (1932), the Sacred Penitentiary ruled that couples could legitimately abstain from the use of marriage during fertile periods for just and grave causes. Together these were taken as an approval of the recently developed rhythm method. Since that time, the Catholic Church has repeatedly affirmed the legitimacy of recourse to NFP for iustae causae (just causes) (e.g., by Popes Pius XII, Paul VI, John Paul II, and Benedict XVI, and in the Catechism of the Catholic Church).

Why then might some think that the SDM is a problem? Our questioner states three possible reasons. The first argues that the method is not 'natural' because a computer model was used to calculate the days of abstinence; therefore, the logic goes, it must be unnatural; since contraception is also 'unnatural,' the SDM must be similar to contraception.

But using a computer to determine facts pertaining to one's fertility cycle is no more intrinsically problematic than using a computer to determine any other facts about one's biology (e.g., blood type, glucose levels, or blood pressure). In this case, the facts are used to assist couples to carry out morally legitimate means of family planning. This enables couples to practice responsible parenthood, which, the Church teaches, is a great human good (cf. Humanae Vitae, no. 10). And technology used at the service of the moral law and human good is not only legitimate, but praiseworthy. If however technology is used at the service of wrongful forms of family planning, then it is used wrongfully.

The second reason is that the SDM has been endorsed by USAID (which has links to abortion funding). This is true. Not only has the SDM been endorsed by USAID, the method was developed (at Georgetown University's Institute for Reproductive Health) by grants in part provided from USAID.

But the fact that USAID is involved in some illicit activities does not mean that everything it does is illicit, nor does it mean that everyone who cooperates with its activities is doing something illicit. By funding the development of a morally legitimate form of family planning, USAID, to that extent, carried out a good act. Using the knowledge derived from that funding is unlikely to enrich USAID and hence equip it to carry out future illicit activity. And that same knowledge is likely to assist large numbers of couples, especially in developing countries, to plan their families in an upright way. Morally conscientious people should encourage USAID to devote more resources to similarly legitimate activities.

The final reason is that some of the literature promoting the SDM has left open the possibility of using a back-up method [of contraception] during the fertile period. This tells us two things: first, that some who promote the method do not think that contraception is wrong and believe that the SDM is just another form of (natural) contraception. In this regard, they are in error. Contraception is wrong to use; and the SDM is not a form of contraception, since for a method to be contraceptive it must aim to render sexual intercourse sterile; and the SDM promotes abstinence, which is the avoidance of intercourse.

Second, it tells us that the SDM can be used wrongfully, as when one uses it in tandem with another form of contraception. But the fact that it may be used wrongfully does not mean that everyone who uses it does so wrongfully. Those couples who understand the integrity of marriage and the marital act, and who abstain from intercourse for just reasons using the SDM, and who do not have recourse to other morally illicit forms of fertility control, do nothing illicit.

Therefore, Catholic (and non-Catholic) married couples may practice and promote the SDM as a licit form of Natural Family Planning. This was affirmed in July 2011 in a pastoral statement by Archbishop Antonio Ledesma, S.J., of the Archdiocese of Cagayan de Oro in the Philippines.

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E. Christian Brugger is a Senior Fellow of Ethics and director of the Fellows Program at the Culture of Life Foundation; and the J. Francis Cardinal Stafford Chair of Moral Theology at St. John Vianney Theological Seminary in Denver, Colorado.


[Readers may send questions regarding bioethics to bioethics@zenit.org. The text should include your initials, your city and state, province or country. The fellows at the Culture of Life Foundation will answer a select number of the questions that arrive.]