Teens who pledge to remain virgins until marriage are more likely to take chances with other kinds of sex that increase the risk of sexually transmitted diseases, a study of 12,000 adolescents suggests. The report by Yale and Columbia University researchers could help explain their earlier findings that teens who pledged abstinence are just as likely to have STDs as their peers. The latest study, published in the April issue of the Journal of Adolescent Health, found that teens pledging virginity until marriage are more likely to have oral and anal sex than other teens who have not had intercourse....