Most sexually active teenage girls know relatively little about sexually transmitted diseases until it is too late, according to new research. In a survey of 300 adolescent girls in the Pittsburgh area, Carnegie Mellon University researchers found that girls who reported having been diagnosed with an STD knew more about that particular disease than other girls, but did not know more about the other diseases. The findings are published in the January edition of the Journal of Adolescent Health. On average, with the exception of HIV/AIDS, the teens did not know many basic facts about STDs, said Julie Downs, lead...