A new study of 1,400 girls finds that the HPV vaccine does not alter sexual behavior. That is, those girls who receive the HPV vaccine do not engage in sexual activity earlier, more frequently, or riskier than those who do not. But what really fascinates about this this study is that it was even necessary:

Since public health officials began recommending in 2006 that young women be routinely vaccinated against HPV, many parents have hesitated over fears that doing so might give their children license to have sex.

HPV is the most common sexually transmitted disease in the United States (nearly a third of teens age 14 to 19 are infected), and it is known to lead to cancer of the cervix, throat, and anus. And yet apparently, some parents would rather let their children die of cancer than have sex. Which they're gonna eventually have anyway.