Peter Gomes claims that it happened, and who is he to exaggerate? Sainted Mother Teresa of Calcutta was at Harvard to receive an honorary degree. When she rose to speak to the assembled graduates in Harvard Yard, many of whom had been aided by alcohol in their enjoyment of the ceremonies, she launched her speech with, “Young people, there is nothing more important than for you to be chaste.”

The graduates sat for a moment in befuddled silence, unsure of what she was talking about.

“You must be chaste; your body is a temple,” she continued.

Some audience members brightened and said to one another, “Yea, I want to be chased! Sure, chase me all you want!” Hoots and shouts of praise accompanied the rest of Mother Teresa’s speech.

That’s how most of us have been taught to regard chastity—as a joke. But now comes Girl Meets God author Lauren Winner with a book aptly subtitled The Naked Truth About Chastity. C. S. Lewis once said that “chastity is the most unpopular of the Christian virtues.” Winner’s book may change that, or at least it may show us why chastity is unpopular—and it is not for the reasons we thought.

Winner begins by admitting that she was unchaste as a teenager and college student. It’s hard to be a successful, upwardly mobile student in America without being adept at hooking up. Winner’s turn toward Christianity convinced her that so-called sexual freedom is just one of the lies our consumer culture tells us about ourselves. Our declarations of sexual liberation are the rattling of our chains, the sure sign that the world has got us.

With a winsome, direct, engaging style full of beguiling humor and verve, Winner forcefully argues that chastity is the most unnatural of Christian virtues. The church must teach us who God has created us to be, must inculcate in us the practices and disciplines that we require if we are to be chaste in a world where it seems like everyone is hooking up with everyone else. While much of the current infatuation with “spiritual practices” is rather thin, in reclaiming chastity as a spiritual discipline Winner gives substance to the notion of practice and thereby gives substance to the notion of church.

To tell the truth, this book is not so much about chastity as it is about the church. Winner demonstrates that one reason mainline churches compose such superficial, theologically empty statements about sex—and one reason we can’t seem to do more than help people adjust to the sexual marketplace with a bit less guilt—is that our community is not strong enough to support a chaste lifestyle. Truthfully, we dare not go out and try to be chaste in a world like ours by ourselves. We mainline Christians have capitulated and fallen face down into the morass of contemporary sexual confusion not simply because we want to be in step with the culture but because our church does not enable us to look at someone like Britney Spears and know why we are meant not to emulate her.

I was pleased that Winner’s concluding chapter is about repentance and forgiveness. If someone like me is going to practice chastity, then I had best be in a church that tells me not only how not to have sex but also how to confess my sin and receive forgiveness when I have sex in a way I ought not.

This book is a great resource for pastors and congregations. Winner defends marriage as a clench-fisted, revolutionary endeavor that is against just about everything we have been taught to believe, and her defense of singleness as the primary vocation of Christians is equally defiant. She also offers practical ideas about what churches can do to support us in our vocations of marriage and singleness.

Real Sex is destined to be one of the most useful books for churches to be published this year. In other words, Lauren Winner has done it again.