In his Bible, Gender, Sexuality: Reframing the Church’s Debate on Same-Sex Relationships, James Brownson critiques the idea that the “image of God” in humanity includes sexual difference:
Throughout much of Christian history, the notion that gender differentiation is part of the image of God (“male and female as the image of God in stereo”) has occasionally surfaced as a marginal voice, but it has never occupied a significant place in the Christian understanding of the imago Dei. The reason is a simple one. If both male and female must be present together in order to fully constitute the image of God, then those who are single do not fully reflect the image of God. This runs deeply against the grain of many passages in the Bible. But even more important, the New Testament clearly proclaims that Jesus is, par excellence, the image of God (e.g., 2 Cor. 4:4; Col. 3:10; 1 Cor. 15:45). Unless we are to postulate an androgynous savior, something the New Testament never even contemplates, we cannot say that the image of God requires the presence of both male and female. It is far better to interpret Genesis 1:27, which insists that both male and female are created in the divine image, to mean that all the dignity, honor, and significance of bearing the divine image belong equally to men and women. We need not delve into the entire debate about what exactly the image of God signifies. For our purposes it is enough to say what is not signified by the divine image: gender complementarity.
One theologian Brownson singles out for criticism is Karl Barth, for whom, Brownson says, “a complementary understanding of gender is essential to the image of God.” Brownson thinks this understanding of the imago Dei would require each person to be married to a member of the opposite sex in order to fully become a divine image-bearer.
But it’s important to see that this is not the conclusion Barth himself draws. Rather, Barth thinks that single people, the widowed, and those who are divorced are still, in their unmarried state, image-bearers. Why? He answers (in Church Dogmatics III/4 §54, with my emphasis added):
It belongs to every human being to be male or female. It also belongs to every human being to be male and female: male in this or that near or distant relationship to the female, and female in a similar relationship to the male. Man is human, and therefore fellow-human, as he is male or female, male and female. But it certainly does not belong to every man to enter into the married state and live in it. The decision to do so is not open to each individual, and there are reasons why it is open to many not to do so. Even then they are still men and therefore male or female, male and female.
What about Brownson’s Christological point—that Jesus was, par excellence, the image of God and yet not “present together” as male with female? For Barth, it is crucial to recognize that Jesus’ celibacy was not a rejection of community—or “co-humanity”—with women (as the Gospels attest, for example, in Luke 8:1-3). As Christopher Roberts summarizes,
On Barth’s terms, sexual difference is still theologically significant for those not called to be part of a couple—such as Jesus. On these terms, it is essential to Jesus’ humanity that he have a relationship as a man with women, but that is not the same as to say that Jesus required a wife or consort. To be celibate rightly is also to declare a choice in response to sexual difference, and Barth would have us regard that Christ’s chastity as a single man is as much a response to sexual difference as marrying. Barth does demand that one must live in encounter with others in the sexual sphere, but that encounter could take the form of a celibacy that upholds chastity between male and female in the community.
Thus, it is not enough to point to Jesus’ celibacy and say, as Brownson does, “If both male and female must be present together in order to fully constitute the image of God, then those who are single do not fully reflect the image of God.” On the contrary, at least according to Barth, those who are single are, in a profound way, “present together” as male and female, not just male or female.