The Catholic Church (i.e., the Pope) thinks that sexual activity in only for producing offspring (I'm not sure where that leaves couples who can't have children, for whatever reason), but I don't know what the scriptural reasoning is. It sounds like an idea pushed by religious leaders who have an issue with their own sexuality, especially now that the Catholic church has a celibate clergy.
Christians have evolved a very different attitude toward sex than Jews and Moslems. In the privacy of their own homes, Jewish and Moslems couples are supposed to go wild with each other (well, within reason).