Amber and I are talking to a bunch of high school students this weekend about sex. Here are some of Frederick's Buechner's thoughts on the subject:
Contrary to Mrs. Grundy, sex is not sin. Contrary to Hugh Hefner, it's not salvation either.
At it roots, the hunger to know a person sexually is the hunger to know and be known by that person humanly. Food without nourishment doesn't fill the bill for long, and neither does sex without humanness.
Promiscuity is an appealing view in that anything goes as long as nobody gets hurt. Who is to say who gets hurt and who doesn't? Maybe it will be years before the X-rays show anything. Maybe the only person who is hurt is you.
Sex is sinful to the degree that, instead of drawing you closer to the other human beings in their humanness, it unites the bodies but leaves the lives inside them hungrier and more alone than before.
Sex can be holy and sacred, after all it is God's idea and without sex the human species would become extinct in about a hundred years or so. Sex can also be secular and profane. As Buechner writes, sex is a lot like nitroglycerin, it can either blow up bridges or heal hearts.
(See Wishful Thinking pp. 107-109)