The term Sexual revolution was coined by Wilhelm Reich in his book The Sexual Revolution. That book was first published in 1945. Reich wrote in the book what he saw as wrong, namely the double standard regarding morals in the society of his time. These double standards and the suppression of the sex drive would make people different. This would lead to a buildup of aggressions and frustration.
Freeing the sex drive would lead to a peaceful change of society, according to Reich.
These ideas meant that some people in the 1960s radically changed their views regarding sex. They were very open-minded about it. The publications of people like Alfred Kinsey helped give wings to the movement.