Half of Young Americans to Get Sex Diseases -Study By Maggie Fox, Health and Science Correspondent WASHINGTON (Reuters) - Half of all young Americans will get a sexually transmitted disease by the age of 25, perhaps because they are ignorant about protection or embarrassed to ask for it, according to several reports issued on Tuesday. The reports, publicized by two nonprofit sexual and youth health groups, said there were 9 million new cases of STD among teens and young adults aged 15 to 24 in 2000. They said the U.S. government's policy of preferring abstinence-only education would only increase those...