booooom

Thailand used to fit the the classic 'virtuous girls, philandering boys' model. At the start of the 1990s, 57 percent of twenty-one-year-old men in Northern Thailand trooped off to the brothel to do their philandering. More than half the sex workers who soaked up their excess energy were HIV-infected....

Then...the Thai economy boomed. Girls were getting better educations than ever before...Educated girls were waiting longer before getting married, but not before having sex. By the end of the 1990s, 45 percent of girls aged 15-21 in northern Thailand admitted to having sex with boyfriends before marriage, compared to less than a tenth of that in a nationwide survey in 1993.

...So at the end of the decade, we have a lot more premarital sex and not all that much condom use with girlfriends. But now that these young, cash-strapped guys can have sex without paying, they've stopped handing over cash for sex. By the end of the 1990s, only 7 percent of young men were paying for sex, and HIV prevalence in sex workers had come down too.

....In short, more women having premarital sex equals less HIV.

Moral of the story you know it yourself.. ;)