In his 1986 book July 20, 2019: Life in the 21st Century author Arthur C. Clarke discusses what sexual relations will be like in the year 2019. He envisions a world in which people "boldly state their desires, no matter how bizarre or specific."
While many of his predictions about sex seem pretty accurate, (assuming few dramatic changes within the next 10 years), the most dated part about his vision of the year 2019 involves the posting of classifieds in a newspaper and sending a response to what we can assume is a physical post office box:
Married white female, 40, seeks well-endowed SWM, 18-28, for 3-month intimate companionship. My husband's hormone treatments (he's 6 months pregnant) have put him out of commission temporarily. You take care of me; I'll take care of you. Electrostimulation okay; as is drug-enhanced orgasm, but prefer partner with original equipment rather than implant. Send photo and vaccination certification to Box 2238.
—Personal ad, The Village Voice (July 20, 2019)
Previously on Paleo-Future: