Which churches support same-sex marriage?

Most Christian denominations accept homosexuality, but will not accept physical homosexual relations (or "gay sex"). Most Christian denominations will not allow gay marriage in the Church because the rule of thumb is that a Christian marriage is supposed to be completed by sex, which many Christians do not believe should happen in a "gay" relationship.

However, some Christians will say that a gay marriage between Christians is as Christian as any other marriage, myself included. An example of a Christian denomination which accepts gay relationships and relations are Quakers (The Religious Society of Friends), however I am unclear on their views of gay marriage.

Another Answer:

First of all 'gay marriage' does not exist. By definition marriage is the union of a male and female. So whatever the union of two gay people is, in the same way that a man cannot give birth, this sort of union cannot be called a 'marriage'.

In law in many countries there IS a provision of a civil partnership where two gay people make a commitment to each other and are recognised in law to be legal partners with the same legal rights as married couples.

Civil partnerships are a relatively new phenomenon, considering homosexuality was even illegal only 50 years ago in the UK. In the Christian Church, the liturgy for weddings has no real provision for civil partnerships. Therefore gay 'weddings' cannot take place as yet.

However, in some denominations a service of blessing canbe offered after a civil partnership so that a gay couple who profess their love for each other can celebrate it both legally and in the presence of God.

There are some more exclusive denominations (such as the Roman Catholics and some Protestant denominations) which do not accept homosexuality and therefore do not offer any form of 'blessing'. The Anglican Church, however, is in a different position. Anglicanism represents a very broad Church from charismatic evangelicals to high-church AngloCatholics. Many churches within Anglicanism have differing views on homosexuality. Therefore the Archbishop of Canterbury recently advised strongly against gay blesings in church for the time being to maintain unity within the church between those who agree with gay blessings and those who don't. However, after much prayer and discussion it is sincerely hoped that one day gay blessings will become acceptable as traditional wedding services.