There’s a common misconception that if contraception is wrong because it’s a way to have sex and not have children, then natural family planning (NFP) is also wrong because it’s a way to have sex and not have children.
However, contraception is not wrong because it’s a way to have sex and not have children. The majority of sexual encounters do not result in children. It’s wrong because intentionally using contraceptives (barriers, chemicals, hormones, withdrawal) is a willful act designed to frustrate the total union of man and woman during sexual intercourse. The remote (or distant) end for a contraceptive act is to prevent a child from being conceived. However, the proximate (more immediate) end, whether intended or not, is the prevention of total unity during sexual intercourse.
Contraception turns the sexual act into a selfish pursuit of pleasure, rather than a loving embrace. Further, it destroys the order toward which sexual activity is directed. NFP, however, allows a husband and wife to engage in sexual intercourse without barriers. Therefore, since the couple is always open to a complete sharing of their persons with one another during sexual union, NFP could not be classified as a contraceptive or some equivalent.
There is nothing immoral about a husband and wife having sex when the wife is infertile and there is nothing immoral about a husband and wife being continent during periods of fertility. No moral law demands that a married couple have sex during fertile periods or abstain from sex during infertile periods.
Contraception proponents, especially those who advocate contraceptive use by married couples, label the hoped-for benefit (spacing out of children) as good. Yet, the object chosen to reach the intended end is ignored or labeled as good, simply because the end is good. The end, therefore, justifies the means, according to these people.
This same logic could be used to justify abortion and infanticide, namely, abortion and infanticide also allow married couples to space out children. “Contraception is always seriously wrong because it is always gravely immoral to adopt by choice the proposal to damage, destroy, or impede the good of human life.”
With NFP, however, both the object (rhythm method, etc.) and end are morally good. NFP allows complete unity and openness to human life in every sexual act, and every sexual act using NFP is ordered toward procreation even if conception is never realized. Further, when a married couple decides to increase the likelihood of having children, NFP can help them determine the most opportune time for intercourse, something contraception clearly cannot do.
Note on hormonal contraceptives: Hormonal contraceptives (the pill, IUDs, etc.) can cause abortions and are, thus, commonly referred to as abortifacients. Chemical contraceptives work in the following way: First, synthetic hormones stop the ovaries from releasing an egg. Second, they thicken cervical mucus making it difficult for sperm to live or move.
Third, they thin the endometrium, the womb’s lining. If the pill fails to prevent the ovaries from releasing an egg and the sperm from reaching the egg, the egg is fertilized, and a human being is conceived. The zygote then makes its way to the endometrium, where it should be able to implant. However, due to the thinning of the endometrium’s lining, the zygote typically cannot implant and an abortion is caused without the woman ever knowing she was pregnant. In America, between 104,100 to 1,894,620 pill induced abortions occur each year. For more information on contraception and NFP, read Catechism paragraphs 2366-2372.
 William E. May, Catholic Bioethics and the Gift of Human Life (Indiana: Our Sunday Visitor: 2013), 99.
 American Association of Pro-life Obstetricians and Gynecologists, Birth Control Pill: Abortifacient and Contraceptive, https://aaplog.org/birth-control-pill-abortifacient-and-contraceptive/, May 24, 2010.