The downside of 'friends with benefits' - CNN.com
Human papillomavirus
HPV is the most common sexually transmitted disease in the United States, according to the Centers for Disease Control and Prevention.
About one in four U.S. females age 14 to 59 has HPV, according to a 2007 study in the Journal of the American Medical Association. The HPV rate was highest -- 44 percent -- for women ages 20 to 24.
HPV is not as common in men, according to a 2006 article in the Journal of Infectious Diseases, but is still "highly prevalent." The study, which looked at 40 studies on HPV and men, found that 56 percent of the reports found that at least one in five men had HPV.
