I've read two good posts on the Evangelical perspective on premarital sex today. The first is on Love, Joy, Feminism, where Libby Anne explains why premarital sex can logically be viewed as a breach of trust if you were brought up to believe that purity until marriage is necessary, but points out that unless you're brought up with that expectation, no breach of trust occurs. The second is on The Way Forward, in which he talks about how "Evangelicals live in denial" about how people in their church actually conduct themselves sexually. Evangelicals, after all, are just like the rest of us, sexually speaking. They're just not as open about it.
I'm sure there are people who remain "pure" until marriage, and then live fifty happy years in an exclusively monogamous marriage. But just because it can happen doesn't mean it should happen. One of the things that worries me most about what Libby Anne terms "purity culture" is the underlying idea that young people should be pushed into early marriages so they can have sex within the holy confines of God-sanctioned monogamy. Marriage, though, is the last thing that anyone should be rushed into. I wonder how many people are caught in unhappy, unloving marriages because they were pressured into marrying too young, before they had enough worldly experience to know what they really wanted.