Societies have seen sexual revolutions repeatedly all throughout history. From the Scriptures, we see that it was a type of sexual revolution that caused God to destroy the cities of Sodom and Gomorrah and in Romans 1, Paul speaks of the unbelieving nations as those who've been given over to a form of sexual revolution as a judgment of God.
In modern history, however, the sexual revolution is generally attributed to a dramatic shift in society that became more open to extra-marital sex. With the onset of various types of contraception, traditional values regarding sex were traded for a more liberal and accepting stance. And because it was now easy to prevent pregnancy, sex outside of marriage was no longer taboo. The sexual revolution had begun.
Yet, it didn't stop there. Not only did fornication become common practice in society, it started to become a sort of rite of passage for teenagers. But worse, the "gay rights" movement began to take shape. In June of 1970, America saw its first formal "gay pride" parade in Chicago which was organized by Chicago Gay Liberation. Other cities, particularly on the West Coast, soon followed suit. Yet, at this time, homosexuality was still largely seen as a deviant sexual perversion by the majority of society and these marches were fringe.
Fast forward fifty years, today, the perception of these deviant sexual behaviors has shifted and the culture has now openly embraced nearly every form of sexual perversion and demonized those who oppose the new paradigm.