SYDNEY BAUER SEX education is emerging as the next battleground in a U.S. culture war over LGBT+ rights, as some conservative state legislators seek to keep discussion of sexual orientation and gender identity out of the nation's classrooms. Lawmakers in three Republican-led states backed legislation this year to let parents take children out of classes covering LGBT+ identity - a step critics said will deprive gay and transgender youth of vital information and fuel discrimination. The governors of Arizona and Arkansas later vetoed their bills, fearing legal challenges, but Tennessee's sex education law came into force in May, with conservatives…