There is a popular narrative that suggests the sexual liberation of the 1960s was fueled by the advent of the contraceptive pill. However, a recent article in the Archives of Sexual Behavior suggests that the birth of the birth control pill may not actually have been the main prompt. Instead, the article points to the rise of penicillin as a treatment for syphilis as the real impetus to get the sixties swinging.
Researcher Andrew Francis hypothesized that the discovery that penicillin was an effective syphilis treatment in the 1940s, and the subsequent, widespread treatment efforts, changed public attitudes about sexual risk. In order to determine whether sexual risk-taking had changed earlier than was previously thought, he looked at several markers for "non-traditional" sex, including gonorrhea incidence and prevalence rates and the rates of pregnancies in teenagers and unwed mothers. Doing so, he found that there was a significant increase in sexual behavior a decade before "The Pill" became available, immediately following the collapse of the syphilis epidemic.
This is a fascinating notion to me. Although the analysis isn't perfect, the data is compelling. The more I muse on it, the more I suspect that this paper may shift the way I think about the history of sexuality in the United States.