Humanae Vitae: Bonding and Babies

| 12-16-AD2013 | [3]

Kevin Aldrich - Bonding Babies

[This article is the third in a continuing series on Humanae Vitae.  Last time I examined the question of what the Church means by responsible parenthood.]

At the very heart of Pope Paul VI’s profound and heroic 1968 encyclical Humanae Vitae is the teaching that the marital act has two meanings which ought not be separated by the couple: the unitive meaning and the procreative meaning. These two meanings can be simplified as bonding and babies. Human freedom can separate them, but it ought not to because God has designed them always to be joined together.

Here I will address two questions: “What are the unitive (bonding) and procreative (babies) meanings of sex?”  and  “Why should my wife and I not separate them?”

The Marital Act

The Church uses the term “the marital act” to refer to sexual intercourse between a husband and wife. This term is appropriate, because sex is proper or “belongs to” married couples, and to no one else. Other people can get sexually aroused and act on that arousal in a variety of ways—none of which needs to be cataloged here. But it is only in marriage that sexual arousal and its consummation find their correct place.

This term is a hard teaching for people to accept. Many people believe they have the right to have sex without procreation. Many also think they have the right to procreation without sex. People are convinced they could lose one or both of life’s two greatest goods: sexual enjoyment and having a child.

It is also hard to accept that Paul VI’s teaching is not a religious dogma, but a precept of the natural law. It is obligatory for every person. It is also knowable, understandable, and practicable by every person.

Here is what Pope Paul VI says about this.

“The Church . . . in urging men to the observance of the precepts of the natural law . . . teaches that each and every marital act must of necessity retain its intrinsic relationship to the procreation of human life. . .” (§11)

This doctrine, the pontiff goes on,

“. . . is based on the inseparable connection, established by God, which man on his own initiative may not break, between the unitive significance and the procreative significance which are both inherent to the marriage act.” (§12)

What does the pope mean?

The Procreative Meaning of the Marital Act

In simplest terms, Paul VI is saying that God designed sex so that when a man and a woman come together a new human being can result. The marital act then has an intrinsic, that is, built in  relationship to human procreation.

This directive is one of those obvious statements that is no longer so obvious to us.

If we turn to biology and look at the male and female reproductive systems, besides being mind-boggled by how amazing they are, we have to conclude that they are completely ordered, that is, designed, to bring a new human being into existence by means of sexual intercourse. On the mother’s part, her reproductive system is also made to gestate that new human life until it is ready to be born, and then to nourish the baby once he or she is born.

From a biological perspective only a sexual act between a man and a woman makes sense. This is not trivial, because our bodies and our biologies are not trivial. We are embodied souls and en-souled bodies. This condition is how God has designed us.

One can look at the catalog of ways that people separate sex from procreation, and easily see how many of them—for example, sodomy—are utterly pointless from the biological point of view. If the fundamental purpose of the reproductive system is to make a baby (just as the purpose of the digestive system is to digest food and the purpose of the senses is to perceive the world around us), then from the biological point of view only sex between men and women is reasonable. Only sex between a man and a woman is natural, that is, conforms to the way human nature is designed.

The Unitive Meaning of the Marital Act

Paul VI, the Church, and the natural law do not conclude, though, that only sexual acts which result in pregnancy are licit.

Recall that Humanae Vitae teaches that the marital act has two significances or meanings. The unitive and procreative meanings—or bonding and babies—are like two sides of one coin. As we have indicated above, the marital act biologically is completely ordained or ordered to procreation. This doesn’t mean that every act of intercourse will result in a pregnancy. In fact, the female reproductive system is designed such that most days in a woman’s cycle are naturally infertile with a relatively small ‘window’ of fertility in each cycle. And even if a woman is fertile, there is no guarantee that pregnancy will occur.

By the “unitive significance” the pope is referring to the loving union of husband and wife. This unity includes, but goes beyond, sexual desire and speaks to the life-long and faithful love that is expressed in many ways, but perhaps most profoundly in sexual intercourse.

The unitive significance of the marital act is the physical, emotional, free, and total gift of love, husband to wife, wife to husband. The procreative significance of sexual intercourse is that in the normal course of events, babies come into the world. It is easy to see these two sides of the coin of the marital act—the loving side and the life-giving side.  People can easily grasp that human nature is so constituted that the bonding leads to babies.


What is not so easy to see, or for people to accept, is the Church’s bold teaching that because God has designed us this way, we should not separate the two meanings of sex. We should not render the sexual act infertile or try to have fertility without sex.

This response is the answer to the question of why spouses should not separate the unitive and procreative meanings of the marital act. We should not separate them, because we are creatures of God, and God designed our sexual natures. Because we are mere creatures, not gods, we humbly choose to exercise the power God has given us in the way God has designed it to be used.

It really comes down to a respect for human nature. It is ironic. We live in a time when almost everyone recognizes our need to respect the laws of nature when it comes to natural ecology. Yet when it comes to the laws of human nature, people are eager to disregard the nature of the human body.

What’s Next?

The next article in this series will address the two “questions of conscience” that husbands and wives need to answer when it comes to exercising responsible parenthood.

© 2013 Kevin Aldrich.  All rights reserved.


• Catechism of the Catholic Church §§2360-2363, §2369.



About the Author:

Kevin lives with his wife and seven children in Springfield, IL. He writes screenplays, TV pilots, novels, non-fiction books and articles, and English and religion curricula. He blogs for the Year of Faith at
  • David Peters

    This makes perfect sense. Thank you for this very insightful article! I’m not Catholic but I am amazed at how much Catholicism makes good sense, and has such an incredible depth.
    God bless, and have a blessed Christmas with your family.

    • Kevin Aldrich

      Thanks, Peter! I’m glad that what the Church says is reasonable seems reasonable to you.

      If you are on Facebook and are so inclined, send me a friend request.

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