Christians have no business being ashamed of sex! We find in Scripture that God created it, called it good, and commanded men and women to participate in sexual intercourse. We should always honor what God has created, as He told Peter: What God has made clean do not call profane (Acts 10:15). But there’s a key idea in that verse (which is expressly talking about food), it’s the idea of “cleanness.” The idea is that what conforms to God’s law and God’s will is right and should not be considered shameful, and yet, what is outside of those boundaries should be regarded quite differently.
When we talk about the relationship between sex and shame there are always two possible avenues that we could go. C.S. Lewis unpacks them in a helpful way. He writes:
Modern people are always saying “Sex is nothing to be ashamed of.” They may mean two things. They may mean “There is nothing to be ashamed of in the fact that the human race reproduces itself in a certain way, nor in the fact that it gives pleasure.” If they mean that, they are right, Christianity says the same. It is not the thing, nor the pleasure, that is the trouble…If anyone says that sex, in itself, is bad, Christianity contradicts him at once. But, of course, when people say, “Sex is nothing to be ashamed of,” they may mean “the state into which the sexual instinct has now got is nothing to be ashamed of.” If they mean that, I think they are wrong…it is everything to be ashamed of. (quoted in Heimbach, True Sexual Morality, 242).
Lewis is great at articulating distinction and here is no exception. Christianity affirms the goodness of sex and of our being sexual beings. But the reality is that our sexuality has been affected by the fall into sin and is therefore not perfect, not pure, and often desires sin and expresses itself in sinful ways. That means that there are ways of engaging in sex that, according to Scripture, should be regarded with shame.
As sinners we are prone to justify all sorts of sin and this includes sexual sin. There are expressions of sexual intimacy that should be regarded with shame. We should disapprove of them, be ashamed of our involvement in them, and teach appropriate appreciation of Biblical sexual morality. Sexual morality, then, is not based on biology or psychology or human opinion, but on God’s law. God deems what is appropriate, and anything outside of those boundaries is shameful.
Sex, then, is nothing to be ashamed of, unless what we are discussing turns out to be sinful. We should always be ashamed of sin, but that is not the same as being ashamed of sex. No Christian has the right to be ashamed of sex.