At a high-stakes gathering starting Saturday in St. Louis, the United Methodist Church’s legislative assembly will debate the place of LGBT people in the church knowing that the outcome could lead to a split in the 12 million-member denomination. The UMC Book of Discipline, the denomination’s rulebook, says homosexuality is incompatible with Christian teaching. It also bans gay people from being ordained as ministers and forbids UMC ministers from officiating at same-sex weddings. Following U.S. public opinion, other Protestant faiths have changed similar rules. Progressive Methodists are pushing hard for the rules to be dropped, and conscientious objectors including an openly lesbian bishop increasingly flout them. Unwilling to stay in a denomination that accepts LGBT clergy and weddings, some churches, including the Houston area’s Windsor Village and Grace Fellowship, are weighing whether to leave the UMC.