Of Mice and Men might as well be required reading in an abstinence-only sex education class for the way it presents sex as frightening, a little gross, and a lot deadly—whether you have it with Curley's wife (blackmail, jail time, death), or with a prostitute (disease, loss of money).
In fact, relationships between men and women are so messed up that George says that he prefers whorehouses to women like Curley's wife—"jail bait"—because with a whorehouse you know what you are getting up front and exactly how much it will cost you. When Whit ranks the two local whorehouses based on their cleanliness and cheapness, you get the feeling that George isn't the only one to see sex as a business transaction. Sex on the ranch is perfunctory and necessary, much like it is for Slim's "bitch," who has just given birth.
But for all these scare tactics, we never see so much as a kiss. Sex may lead to death and despair, but at least everyone keeps their clothes on.