The pagan world is sex-obsessed and sex is an idol of our age but telling pagans that sex points them to Christ is not an apologetic or evangelistic strategy we should employ. It is not a biblical strategy. When Paul condemns the sexual immorality of the Greco-Roman world in Romans 1 he preaches the law. He never treats heterosexual sex as a gospel witness or a gospel sacrament. We preach the law to pagans because it is through that message, as Paul showed at the Areopagus (Acts 17), that God the Holy Spirit is pleased to operate to bring his elect to new life and true faith. When people are cut to the quick, as at Pentecost (Acts 2), we preach the gospel of the resurrected Christ as did the Apostles. Some will believe and some will not. Blessed be the name of the God who is sovereign over the sheep and the goats.