The XX Factor

Did Penicillin Cause the Sexual Revolution?

A bunch of dirty hippies heading off to not get syphilis.

Shutterstock/William Perugini

Ask most people to account for the sexual revolution of the 1960s and they will likely say something about improved access to birth control (as well as improved access to Jefferson Airplane and shrooms). But Andrew Francis, an economist at Emory University, wants to give a little credit to penicillin, too.  

What does the antibiotic have to do with free love? In 1943, scientists discovered that it could treat the STD syphilis, which had been spreading steadily across the United States—and especially through the army. As penicillin shots became more available in the ‘50s, syphilis deaths declined and risky sexual behavior—as measured in gonorrhea rates, teen pregnancies, and illegitimate births—increased. These indices of erotic adventurousness, in other words, were rising way before abortion and the pill became an accepted part of women’s reproductive lives during the ‘60s and early ‘70s.

Of course, penicillin didn’t cause the swinging ‘60s full stop. Many historians credit progressive social forces that were already germinating in the straight-jacketed ‘50s. The legalization of the pill and the growing acceptance of abortion couldn’t have hurt either. (Also, correlation does not equal causation, as NPR’s health blog notes.) But Francis does make a suggestive case for penicillin’s contribution to the decade’s freewheeling ways, linking the rise in sexual risk-taking after the syphilis epidemic deflated to the rise in same after a new AIDS treatment came out in 2000.

The study proposes another weird/ironic chain of cause and effect too. Because “the advent of penicillin may have produced analogous effects on sexual behavior as the advent of HAART [an anti-retroviral drug],” Francis argues, it’s possible that the “spread of HIV may have been facilitated by the collapse of syphilis.” In other words, people were less worried about doing it once syphilis left the picture, so they didn’t take the precautions that might have safeguarded them against AIDS. Francis, the economist, thus offers a few words of caution to health policy makers: “To focus exclusively on the defeat of one disease can set the stage for the onset of another if preemptive measures are not taken.”

But that shouldn’t stop us liberated women from silently offering penicillin a prayer of thanks next time we embrace the legacy of free love.