Sex comes in three varieties: procreative, relationship-affirming, and recreational. Humans have always indulged in all three. But from Biblical times through the 18th century, the only God-fearing justification was procreation. This made some sense in an agrarian economy where more children meant more hands to work the fields.

The Industrial Revolution changed that. Urbanized factory work led to smaller families, and religious thinking changed. God’s favorite reason for sex remained procreation, but as farming yielded to wage labor, theologians decided the Almighty also approved of sex to affirm relationships.

Meanwhile, Western culture has always included an undercurrent of recreational nookie: mistresses, sex work, group sex, and other types of erotic exuberance.

Over the past 70 years, researchers have confirmed the tremendous diversity of sexuality, shattering all illusions that Americans get down only for God’s two approved reasons. The large majority of Americans have enjoyed some forms of recreational sex, and many routinely play that way.