One day, when I was about eight years old, during a creative dramatics class where the teacher seemed willing to talk about anything, I blurted out a question that had been on my mind for a while:

"How did sex get started?"

The teacher, a woman in her twenties, was caught off guard. She hemmed and hawed for a moment, but I persisted:

"How did the first men and women figure out how to have sex?"

I still remember the teacher’s attempt at an answer, because it was so odd. She made up something vague about how perhaps the woman gave off a certain smell that drew the man over to have sex with her. It sounded sufficiently gross to throw me off track, but it wasn’t really an answer.

Eight years later, when I was a senior in high school, my question changed to the far more common "How do I start having sex?" But my experiences never taught me how sex got started—which is to say, why it got started. What is sex for? We know that sex is for reproduction. A strict materialist—that is, someone who believes that all thoughts may be traced to physical causes—would tell you that the feelings of intimacy one has during sex are simply biological trickery to get us to want to propagate the species. (Why biology would care whether we propagate the species is never explained.)

On the other hand, if you believe that what transpires between a man and a woman during sex has its source in something other than the couple’s DNA, their upbringing, and what they had for lunch, then sex must have a function that goes beyond creating more people to have sex.

During the past quarter century, Christianity has found a new way to state the answer to the question, What is sex for? It’s called the "theology of the body." A deeply profound interpretation of basic principles found in the Bible, it’s formulated in terms that contemporary people of faith can understand, and woven together like a seamless garment with the meaning of life itself.

First articulated by Pope John Paul II, the theology of the body is espoused by mainline Protestant denominations as well as Roman Catholicism. Focus on the Family, the Protestant ministry founded by Dr. James C. Dobson, offers several helpful articles based on the theology of the body at pureintimacy.org, and there are many good books on the subject, such as Christopher West’s Good News About Sex and Marriage. These are fascinating, life-changing resources, and I can’t recommend them highly enough if you’re looking to explore what Christianity has to say about the deep and mystical meaning of sexual union between man and wife.

The theology of the body starts in Genesis, with God’s creating man in His image. God is invisible. By giving us our bodies in His image, He has made the invisible visible, the intangible tangible.

So our bodies are living metaphors of God’s loving nature—but more than metaphors, because God, in creating us, breathed His Spirit into us. This divine origin of our bodies gives what we do with them meaning beyond the superficial. When we use them as God has instructed us, especially when we take part in something sacred, we are making visible a hidden mystery—bringing to earth a bit of heaven. This may be seen in baptism, when, in being washed with water—the means we normally use to cleanse our bodies and make us feel new—we instead are cleansed in our souls and made into literally new creations. It may also be seen in Communion, when God uses the most mundane physical processes of eating and drinking to bring forth a metaphysical experience where we touch eternity.