[When you’re done here, see the follow-up: Sexuality and Theology — A running start]
In my experience, there may be no bit of Protestant theology more impoverished than our understanding of sex and sexuality. I usually see one of two approaches:
1) Ignore it entirely. Perhaps because we don’t know what to say or because we’re embarrassed about what we’ll say. Perhaps because our theology generally suffers from a dualism that wants only to deal with “spiritual” things and treats the physical world as either irrelevant or something to be shunned. (We see that in songs like “Absent from flesh! O blissful thought!” and “I’ll Fly Away.”)
2) Argue over very specific rules about sex — namely, who should be having sex and who shouldn’t — while generally disregarding any bigger picture. Some people/groups will cite a few particular Bible passages and argue one way. Others will argue against any of those rules, citing things like cultural sensitivity, hospitality, grace, and open-mindedness.
Neither of these approaches seems interested in a deeper theology of sexuality. 
As a pastor, I’ve realized that the Church isn’t preparing its people for how to live as sexual beings. We may tell them when they can and can’t have sex, and with whom, but that’s about it. What do we have to say to single men and women about their (wo)manhood? To those singles — or to couples struggling with fertility — who ask what it means that God has created them with an innate sense for fatherhood and motherhood? My toolkit has proven too basic for those situations — and what’s in it feels more like shallow clichés than robust theology.
Jesus and Sex
Twice, the Pharisees and Sadducees try to trip up Jesus by asking him about issues concerning marriage and sexuality.
I’m not sure those Pharisees are very unlike many in evangelical world today: cite a Bible verse and make a rule. They ask, “What are people allowed to do, and what are they prohibited from doing?” Give them an answer, and they’re fine to run along.
But in that encounter, Jesus points beyond Moses. All the way back to creation. Now we’re not just dealing with rules that have been set, we’re dealing with a whole theology of creation. And when the Pharisees challenge him — asking why Moses could say something so much more permissive than what Jesus expects — Jesus says it’s because their hearts were too hard to live according to the proper standard. Yes, there was a rule in place, but it doesn’t capture the truth at its heart.
When the Sadducees ask about marriage after the resurrection (a clear trap — they don’t believe in resurrection; Matthew 22), they seem not far from the skeptic who asks if God can create a rock so heavy that he can’t lift it.  Their question isn’t a serious inquiry seeking an answer. It’s a way to prove their position by the absurdity of the possible answers.
But we get in Jesus’ response a brilliant glimpse into the true final ends of marital relationships. So while the Sadducees try to use an example of marriage to show the absurdity of a future resurrection, Jesus shows them that their problem is their understanding of marriage in the first place.
Sexual Theology in the Web
My purpose here isn’t to start giving answers about a theology of sexuality. To even begin doing justice to that will take numerous posts — or a book.  Next week, I’ll post the audio to my sermon, “Eucharist and Sexuality,” which at least gives a running start.
My purpose here is to demonstrate our need for what I referred to as a webbed theology in my last post. I’m sure the Pharisees and Sadducees were, in many regards, thoughtful and careful theologians. But when it comes to sexuality, the examples we see show groups that are simplistic and superficial, looking narrowly at Moses’ laws in Scripture to make their laws and arguments. I don’t think we’re doing much better today.
Jesus shows that there’s more to it. Want to understand marriage and divorce and sexuality? Then you need to understand creation. Which means you’ll need to get into mankind’s creation in the image of God. Which leads to the heart of the image of God — the Trinity.
Want to understand marriage and sexuality? Jesus shows that you need to understand eschatology — the part of theology dealing with our final destiny.
We’ll have to get deeply into an understanding of Christ’s incarnation and the church as the bride of Christ (ecclesiology), which I’m coming to believe get right to the heart of a proper theology of sexuality. And we’ll need to work out a theology of desire and delight, to boot.
Those last three paragraphs may show most clearly why evangelicals have an anemic theology of sexuality. That theology depends on a robust ecclesiology, which hasn’t been a strong suit for us. It depends on a theology of desire and delight, which I don’t think I’ve ever heard discussed (we’ll need to go to Augustine for things like this). And it means getting past debates about creation and evolution so that we can ask some more important theological questions about creation.
Note: Tim Tennent has begun a more detailed exploration of some of the themes I’ve just begun to hint at here. Take a look at his series “Marriage, Human Sexuality, and the Body” — part I, part II, part III.
See more: Sexuality and Theology — A running start.
1. When I asked a friend — one of the best theological thinkers I know — for some resources on the subject recently, he suggested I go to Europe and the Anglicans and Roman Catholics. He said he wasn’t aware of any good evangelical theology being done in this area — or American theology, in general. We evangelicals seem pretty blissful in our ignorance and superficial approach to sexuality.
2. For what it’s worth, this is more of a word game than a genuine, philosophical problem. Can God make a round square? No. Not because God isn’t all-powerful, but because it’s a violation of definitions.