A provocative theory set by US Economist Andrew Francis denies a common assumption that the sexual revolution began in the 1960s, fuelled by the introduction of the birth control pill and a heavy mix of sex, drugs and rock and roll. The theory says that themodern sexual era and the spreading of 'risky sexual behaviour' actually began a decade earlier, as the widespread use of penicillin drastically brought down levels of syphilis. By looking at historical data from the last 70 years, researchers found that it was actually the 1950s when the levels of illegitimate and teen births as well as cases of gonorrhoea surged to record highs. Before, people were frightened by syphilis that caused blindness, dementia and paralysis -and killed around 20,000 people a year in the United States alone. Knowing that they were now safe from these diseases, people changed their sexual habits accordingly. Andrew Francis said that these findings are significant in the fight against HIV and AIDS too, as currently revolutionary tendencies in the sexual lifestyle, related to development of antiretroviral therapy, have made people less worried about HIV and made them more likely to engage in risky sexual behaviour. Comparing sexual behaviour to economic law, Francis called up policy makers to take into consideration that sexual behaviour responds to incentives, because focusing exclusively on the defeat of one disease can set the stage for the onset of another if pre-emptive measures are not taken.