Equalities minister Maria Miller said Tuesday the bill will authorize same sex civil unions, as well as religious marriages if religions decide to "opt in." But she says the legislation will make it unlawful for the Church of England and the Church of Wales - the established churches in those countries - to conduct gay weddings.
Since 2005, gay couples in Britain have been able to form civil partnerships, which carry the same legal status as marriage.
Plans to introduce same-sex marriage have been opposed by the Anglican and Roman Catholic churches.
Some religious groups, including Quakers, say they want to conduct same-sex ceremonies.