In the last five years, the debate over gay marriage has been heard in the halls of the U.S. Congress, at the White House, in dozens of state legislatures and courtrooms, and in the rhetoric of election campaigns at both the national and state levels.

While the gay marriage controversy has many elements, including disagreements over religious and social norms, much of the debate is a legal one.

In recent years, same-sex marriage has been a contentious subject within many religious groups in the U.S. Here is an overview of where 16 religious groups stand on this issue.

In many countries around the globe, the institution of marriage is in flux as governments consider whether to allow gay and lesbian couples the right to marry or enter into other legally recognized forms of domestic partnership. Currently, countries around the world, mostly in Europe, offer varying levels of marriage rights to gay couples.