National Marriage Week: Why does sexual difference matter at all? Why does it matter for marriage?
Happy Valentine’s Day! Today is the last day in National Marriage Week, and the last in our series on sexual difference.
So far in the series, we’ve looked at various ways that our culture describes sexual difference (part one and part two), examined Scripture and the Catechism on the subject, and added two helpful phrases to our repertoire of describing sexual difference (“asymmetrical reciprocity” and “double unity”). One important point remains to be discussed: Why does sexual difference matter?
Difference: the foundation of love
Before considering sexual difference specifically, let’s take one step back: why does difference matter? 
Our culture seems a bit schizophrenic on the topic of difference. On the one hand, it loudly celebrates “diversity” and the virtue most in vogue is, of course, “tolerance” for people different from you. But on the other hand, difference – especially between men and women – is often treated as suspect, as a thin veneer over inequality. In other words, equality is confused with sameness.
But in a world where everything is the same, love would be impossible. G.K. Chesterton explains why:
“I want to love my neighbor not because he is I, but precisely because he is not I. I want to adore the world, not as one likes a looking-glass, because it is one’s self, but as one loves a woman, because she is entirely different. If souls are separate, love is possible. If souls are united, love is obviously impossible. A man may be said loosely to love himself, but he can hardly fall in love with himself, or, if he does, it must be a monotonous courtship.” – Orthodoxy (Peabody, Mass.: Hendrickson Publishers, 2006), 128.
Difference, in other words, is what saves us from the fate of Narcissus. Difference – recognizing the other as other – is what prevents us from becoming entranced with our own reflection in a shoddy imitation of love.
But even if we accept Chesterton’s point and agree that difference is necessary for love, we might be tempted to think that sexual difference is just one of many differences between persons, such as race, height, or taste in music. What is unique about sexual difference, compared to other possible differences?
Taking bodily life seriously
First, the reality is that being human means being a man or a woman, embodied as male or female. (Even the difficult situations of those born with ambiguous genitalia are the exceptions that prove the rule. An intersex or hermaphroditic condition is not a new gender, but a combination of male and female characteristics.) Taking sexual difference seriously allows us to take the body seriously. It allows us to treat the body as an integral part of our identities, instead of a cage or shell. We are men or women both body and soul. We don’t just have a body—we are our bodies. (See the Catechism, nos. 362-368 on the human person as a unity of body and soul.)
Distinguishing in order to unite
Second, sexual difference is unique because it is inherently referential. Unlike other differences between individuals (height, ethnicity, etc.), which do not require the presence of an “other” to be understood, the bodily reality of a man is only fully understood in light of the bodily reality of a woman. Recall the point in part three of this series: the generic “Adam” is first referred to as “male – ˈiš” when he encounters Eve, the first “woman – ˈiššāh” (see Gen 2:18-25).
But the uniqueness of sexual difference doesn’t end there. The “referential” difference between man and woman does not simply distinguish between the two; it also serves as the foundation of their unity. Or, more accurately, sexual difference distinguishes in order to unite. Only because a man and a woman are sexually different are they capable of forming a complete union of body-persons; if they were the same, no such union would be possible.
In fact, the sexually-differentiated body reveals that man and woman are fundamentally “for” each other. As Bl. John Paul II explained, “The body, which expresses femininity ‘for’ masculinity and, vice versa, masculinity ‘for’ femininity, manifests the reciprocity and the communion of persons” (TOB, 14.4; see also Catechism, no. 371). Being male or female is not simply a matter of biology or anatomy; it is a witness to the call to love and communion that is inscribed within man and woman’s identity as body-and-soul (see FC, no. 11).
Open to the gift of the child
A third reason why sexual difference is unique is because it – and only it – makes two persons capable of welcoming a new child into the world. The “supreme gift” of the child (see GS, no. 50) depends on the sexual difference between father and mother. The spouses’ capacity for procreation, in turn, ensures that their sexual love does not become egotistic, an enclosed circle. The unity of spouses, wrote John Paul II, “rather than closing them up in themselves, opens them up towards a new life, towards a new person” (LF, no. 8).
The difference is the difference
To sum up: Difference is necessary for love; if all were one, love would be impossible. Love requires recognition of the “other” as “other.” But while there are many differences between persons, sexual difference – the difference of man to woman and woman to man – is a unique kind of difference. It is irreducible and primordial, fundamental to human nature and every human experience. In particular, it is the avenue toward full personal-bodily communion between a man and woman, and thus is necessary for a couple to experience the superabundant fruitfulness of conceiving a child. Both of these capacities – for union and for children – matter for marriage. In fact, they are essential for marriage. This helps us to understand why sexual difference – the difference of man to woman and woman to man – is an essential aspect of marriage. Without it, marriage is impossible.