Is there any one aspect of human life that has affected every other aspect of human life more than being male or female?
While my life is certainly not reducible to being a man, everything about my life is shaped by the fact that I am male, not female.  My wife’s whole life is shaped by being a woman and not a man. Each of my nine children (yes, we wanted to start our own baseball team) are unde­niably and monumentally shaped by being boys or girls. And yet how often do we stop to think that it didn’t have to be this way?
God didn’t have to make two different kinds of human beings. He didn’t have to make us so that men and women, on average, come in different shapes and sizes and grow hair in different places and often think and feel in different ways. God could have propagated the human race in some other way besides the differentiated pair of male and female. He could have made Adam sufficient without an Eve. Or he could have made Eve without an Adam. But God decided to make not one man or one woman, or a group of men or a group of women; he made a man and a woman. The one feature of human existence that shapes life as much or more than any other—our biological sex—was God’s choice.
In an ultimate sense, of course, the world had to be made the way it was, in accordance with the immutable will of God and as a necessary expression of his character. I’m not suggesting God made Adam and Eve by a roll of the dice. Actually, I’m reminding us of the opposite. This whole wonderful, beautiful, complicated business of a two-sexed humanity was God’s idea. “So God created man in his own image, in the image of God he created him; male and female he created them” (Gen. 1:27). The whole human race is, always has been, and will be for the rest of time, comprised of two differentiated and complementary sexes. This perpetual bifurcated ordering of humanity is not by accident or by caprice but by God’s good design.
And why?
What is at stake in God making us male and female? Nothing less than the gospel, that’s all. The mystery of marriage is profound, Paul says, and it refers to Christ and the church (Eph. 5:32). “Mystery” in the New Testament sense refers to something hidden and then revealed. The Bible is saying that God created men and women—two different sexes—so that he might paint a living picture of the differentiated and complementary union of Christ and the church. Ephesians 5 may be about marriage, but we can’t make sense of the underlying logic unless we note God’s intentions in creating marriage as a gospel-shaped union between a differentiated and complementary pair. Any move to abolish all distinctions between men and women is a move (whether intentionally or not) to tear down the building blocks of redemption itself.
Men and women are not interchangeable. The man and the woman—in marriage especially, but in the rest of life as well—complement each other, meaning they are supposed to function according to a divine fitted-ness. This is in keeping with the order­ing of the entire cosmos. Think about the complementary nature of creation itself. “In the beginning, God created the heavens and the earth” (Gen. 1:1). And that’s not the only pairing in creation. We find other sorts of couples, like the sun and the moon, morn­ing and evening, day and night, the sea and the dry land, and plants and animals, before reaching the climactic couple, a man and a woman. In every pairing, each part belongs with the other, but neither is interchangeable. It makes perfect sense that the com­ing together of heaven and earth in Revelation 21–22 is preceded by the marriage supper of the Lamb in Revelation 19. That God created us male and female has cosmic and enduring significance. From start to finish, the biblical storyline—and design of creation itself—depends upon the distinction between male and female as different from one another yet fitted each for the other.
Sexual difference is the way of God’s wisdom and grace. It was there in the garden, there in the life of ancient Israel, there in the Gospels, there in the early church, will be there at the wedding supper of the Lamb, and was there in the mind of God before any of this began. To be sure, manhood and womanhood is not the message of the gospel. But it is never far from the storyline of redemptive history. The givenness of being male or female is also a gift—a gift to embrace, a natural order of fittedness and func­tion that embodies the way the world is supposed to work and the way we ought to follow Christ in the world. Let us, then, as male and female image bearers, delight in this design and seek to promote—with our lives and with our lips—all that is good and true and beautiful in God making us men and women.
This article is adapted from the opening chapter and closing section of my new book, Men and Women in the Church: A Short, Biblical, Practical Introduction published by Crossway.

Kevin DeYoung (PhD, University of Leicester) is senior pastor of Christ Covenant Church in Matthews, North Carolina, Council member of The Gospel Coalition, and associate professor of systematic theology at Reformed Theological Seminary (Charlotte). He has written numerous books, including Just Do Something. Kevin and his wife, Trisha, have nine children: Ian, Jacob, Elizabeth, Paul, Mary, Benjamin, Tabitha, Andrew, and Susannah.