American squeamishness about talking about sex has helped keep common sexually transmitted infections far too common, especially among vulnerable teens, U.S. researchers reported Monday. Latest statistics on chlamydia, gonorrhea and syphilis show the three highly treatable infections continue to spread in the United States. "Chlamydia and gonorrhea are stable at unacceptably high levels and syphilis is resurgent after almost being eliminated," said John Douglas, director of the division of sexually transmitted diseases at the U.S. Centers for Disease Control and Prevention. "We have among the highest rates of STDs of any developed country in the world," Douglas added in a...