ATLANTA—The United Methodist Church plans to split into 2 denominations later this year, church officials said on Friday, a schism that follows years of contention over whether the church should end its ban on gay marriage and ordination of gay clergy.The plan, if approved at the church's worldwide conference in Minneapolis in May, would divide the third-largest US Christian denomination into two branches: a traditionalist branch that opposes gay marriage and the ordination of lesbian, gay,