Page Summary

In order for sexual activity to be good, four characteristics are needed:

  1. Consent: if it isn’t freely given, it isn’t love.
  2. Commitment: the more that a concern for the good of the other person extends beyond the duration of any particular sexual encounter, the more likely that encounter will be rooted in love rather than use.
  3. Completeness: if the commitment is incomplete, is it really love or just a transaction?
  4. Communion: is each person open to unity with the whole of the other person, including the unity that could result in children?
A completely committed consent to communion is also known as “marriage“.

What are the necessary conditions for sexual activity to be good?

Sexual activity is good only when it is a completely committed consent to communion.

Ok, but what does that actually mean?

Sex is good.1 So how does it go so wrong? Recent history, especially the MeToo movement, has demonstrated beyond doubt that distortions of sexual activity are more widespread than commonly thought. What are the crucial differences (true for Christians and non-Christians alike) between sexual activity in its naturally good expression and sexual activity in its morally disfigured expression?

The most obvious factor is mutual consent. If an individual is involved in sexual activity without sufficient consent of the will, that person is the victim of an intrinsically wrong violation of justice. If it isn’t freely given, it isn’t love.

a couple embracing
a middle-aged couple embracing

As straightforward as it seems, notions about consent differ widely. While some incorrectly believe that it is given by the mere absence of a “no”, others believe that it must always be confirmed repeatedly in a way which many people (men and women alike) feel is an obstacle to intimacy. While communication is generally a good thing, some people want to be loved without having to make their desires explicit. But then, that line of reasoning is often used by abusers to justify wrongdoing. This confusion is more likely to happen when less communication has taken place, as in the case of casual sex between people who are not in a committed relationship.

Perhaps commitment should be added to consent. The more that a concern for the good of the other person extends beyond the duration of any particular sexual encounter, the more likely that encounter will be rooted in love of the person for her own sake. If that commitment is absent (as in a one-night stand, though not limited to that), sexual activity is more likely to serve as a way to use the other person for physical or emotional gratification. To engage in sexual activity without commitment implicitly allows the possibility of separating from the other in the future. To engage in sexual activity with someone with commitment implicitly excludes the possibility of separating from the other in the future.

But commitment isn’t just a question of yes or no, but of how much. It’s possible for a sports fan to be committed to multiple teams. Parents are morally obligated to commit to all their children rather than any one above the others, as long as they’re able. Is it the case that a person can morally be committed to a sexual partner for only a term, or even committed to multiple sexual partners? If the commitment is conditioned by a term limit (other than death) or is forced to share attention with competing commitments, is it really love or just a transaction? A transaction involves the exchange of one limited good for another. Love is a complete gift of self, forsaking all others.

So far, we have a completely committed consent, but consent to do what? There are a variety of activities which people perceive as sexual, not all of which strictly qualify as sexual intercourse. Is it whatever the couple finds pleasurable? Making pleasure the decisive factor of sexual love has at least two drawbacks.

First, pleasure changes over time. The same, equally loving act might be more pleasing at one time and not very pleasing at other times. This is even true in non-conjugal situations, such as cooking dinner for extended family. The cook might derive a great deal of satisfaction from devoting his skill and effort to his loved ones, or he might just find it stressful. Whether pleasure is present or absent, it’s still loving, as long as he chooses it.

Second, pleasure doesn’t necessarily involve closeness. Two people can live far apart and experience pleasure, even simultaneously and with the other person in mind, but that would not make it love. Every love, whether sexual or not, involves some sort of union, as detailed on a previous page. In a specifically sexual context, the union which is desired encompasses the whole of the other person, body and soul. To only desire the pleasure, which signals the goodness of that union, and not the union itself is to mistake the road for the destination. And nobody wants to be stuck in traffic, they want to get home.

This union is realized in two respects. The first, sometimes called the “unitive meaning”, is the reciprocal or mutual self-giving which binds a man and woman together. The second, sometimes called the “procreative meaning”, is the openness to becoming one in the generation of new life.

As will be shown in more detail later, children are not disconnected from the union between a man and a woman. Their very existence embodies that union as its own abiding, objective reality. This does not mean that the couple must actually conceive children every time they have sex, or ever conceive. It merely means that they must not actively frustrate that possibility when they perform the kind of act that results by its nature in new life. If they aren’t open to that, then they aren’t willing to be truly united, which is the point of love.

Sexual activity is self-contradictory if the couple uses some means to obstruct either the unitive meaning or the procreative meaning in which their union finds its concrete fulfillment.

Just as talking on a video call is different from talking in person, so also the mere mutual experience of pleasure is different from a one-flesh union. If both options are available, why would anyone choose the video call unless they didn’t want to be in a room together? Similarly, why would anyone choose sex while impeding the unitive or procreative dimensions unless they didn’t want to become one?

Therefore, for sex to be truly loving, it must involve a completely committed consent to communion.

This is what is known as “marriage”.


Have you not read that from the beginning the Creator ‘made them male and female’ and said, ‘For this reason a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh’? So they are no longer two, but one flesh. Therefore, what God has joined together, no human being must separate.

Jesus of Nazareth, Matthew 19:4-6

1) Note about how we’re using the phrases “sexual activity” and “sexual relationships”: strictly speaking, all relationships between embodied people are sexual in some way. The term covers more than just the specific set of activities informally referred to by “sex”, but on this site we’re using the term in this specialized sense to avoid making the reader uncomfortable with graphic language like “genital activity”.

family photo

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