I guarantee you--the Missouri Synod branch of the Lutheran Church will NEVER allow gay marriage in its churches.
Oh, there are groups within all of these denominations that would never go along. The Episcopalians are getting ready to split over the homosexual bishop issue. The Presbyterians have fractured, the Lutherans are fractured, so are the Methodists for that matter. The only reason the Episcopalians haven't done so already is because they have reconciled the unreconcilable.
The Lutheran Church may not, but what about the United Mehtodist Church? Here is their statement on "Equal Rights Regardless of Sexual Orientation"
"Certain basic human rights and civil liberties are due all persons. We are committed to supporting those rights and liberties for homosexual persons."
"We see a clear issue of simple justice in protecting their rightful claims where they have shared material resources, pensions, guardian relationships, mutual powers of attorney, and other such lawful claims typically attendant to contractual relationships that involve shared contributions, responsibilities, and liabilities, and equal protection before the law."
Does not sound like they are too far away from gay marriage.