It's really unfortunate that we Americans are so hung up about sex. We are deeply conflicted and preoccupied by it. Our advertisements, books, films and music are saturated with sexual content, yet we agonize like Puritans over whether these messages are unhealthy. We preach abstinence and chastity, yet we have one of the highest rates of unwed mothers and STDs in the world. We have an unusual, immature fascination with sex partly because we are so torn about it.
As JaTo pointed out, this cultural confusion is largely a product of our judeo-christian heritage. Christians say we must not have sex outside of marriage (even married people are only allowed to have sex to procreate, according to some Christians). And there is plenty of biblical language that treats sex, sexual desire, and the human body as smutty, not something to be enjoyed and celebrated.
But we are biologically programmed to have as much sex as possible. We have succeeded as a species partly because we have virtually constant sex drive. Unlike many animals, we have the physical capacity and desire to have sex at almost any time.
Something has to give.
Biology always wins in the long run. Christianity has only been around for two thousand years, a drop in the bucket of human civilization. Before Christianity, we had other ways to control behavior, such as Confucian teachings, tribal rules, the Code of Hammurabi, and so forth. Even today, most societies get along just fine without biblical sexual taboos (and the guilt trips associated with them). Over time, Christian prohibitions about sex will fade away. Lots of other Christian teachings and values and traditions have fallen by the wayside over the centuries; ask any theologian or historian.
Many Asian, Pacific Island, African and European societies are much more relaxed about sex than we are. In many countries, young people do what comes naturally, without undue guilt and confusion. I don't mean they are having non-stop orgies over there. By all accounts, they really aren't more sexually active than we are. I just mean that young couples don't go around worried about their souls burning in hell just because they are getting some nookie.
