In this Feb. 10, 2011 photo, Oliver Hamilton, 17, top, poses for a photograph with classmates Daniel Alexander, 18, left, Robert Kline, 18, bottom, and Rayhannah Dar, 18, at The Urban School of San Francisco in San Francisco. To get his classmates to appreciate how serious the HIV virus really is, one senior at a San Francisco high school is taking an uncommon approach: He's organized a classwide HIV testing day in the school gym. (AP Photo)

In this Feb. 10, 2011 photo, Oliver Hamilton, 17, top, poses for a photograph with classmates Daniel Alexander, 18, left, Robert Kline, 18, bottom, and Rayhannah Dar, 18, at The Urban School of San Francisco in San Francisco. To get his classmates to appreciate how serious the HIV virus really is, one senior at a San Francisco high school is taking an uncommon approach: He's organized a classwide HIV testing day in the school gym. (AP Photo)