As English law stands, a marriage is between a man and a woman and marriage is effected either by a religious ceremony or by a civil marriage entered into before a Registrar. (Civil marriages have been recognized as a legal alternative to religious marriages since 1837 - Marriage Act 1836).
The Civil Partnerships Act 2004 (fully in force from 5th December 2005) enabled same sex couples to enter into a 'civil partnership' which has almost the same legal effects as a marriage between a man and a woman. See Parliament - Same sex marriage and civil partnerships
The Bill (as introduced into Parliament) has 18 sections and 7 schedules.
Clause 1 therefore makes same sex marriage lawful and specified how such a marriage may be solemnized. Clause 1(3) only has relevance to the Church of England and Clause 1(4) ensures that members of the clergy are not under a DUTY to marry same sex couples.
Clause 2(1) states that a person may not be compelled to (a) undertake an opt-in activity, or (b) refrain from undertaking an opt-out activity. These activities are defined in Clause 2 and include, as an example, giving consent to a same sex marriage.
This clause therefore appears to meet the concerns of some religious bodies that they might be forced by law to conduct same sex marriages.
Clauses 3 to 6 are concerned with amendments to the Marriage Act 1949. Clause 7 with death bed marriages.
Clause 8 is a power to allow for same sex marriage in Church in Wales. The Lord Chancellor is given a role here but he can only act when the Governing Body of the Church in Wales resolves to allow same sex couples to marry according o the rites of the Church in Wales.
Clause 9 is lengthy. Essentially, it enables parties to a civil partnership to become married if they so wish. The process will be governed by Regulations to be made by the Registrar General with the consent of the Secretary of State. If a civil partnership is converted then the civil partnership ends BUT the marriage is backdated to the time when the civil partnership began.
Clause 11 is also lengthy. Essentially, it seems to give the same effect in the law to same sex marriage as to opposite sex marriage. All the law of England and Wales (with the exception of certain Church of England legislation) will have the same effects on both forms of marriage.
Clause 12 refers to the situation where one party to a same sex marriage undergoes a change of gender. This is a potentially complex area. The following is taken from the detailed Explanatory Notes issued with the Bill.
"At present transsexual people who are married or in a civil partnership must end their marriage or civil partnership before a full gender recognition certificate can be issued. This is achieved by the Gender Recognition Panel issuing an interim gender recognition certificate to married applicants and applicants in civil partnerships which causes the marriage or civil partnership to become voidable. Applicants then have six months from the date of issue of the interim gender recognition certificate to apply to the court to end their marriage or civil partnership. Once a marriage or civil partnership has been annulled (or a divorce or dissolution has occurred in Scotland) the court can issue a full gender recognition certificate.
The Spectator 11th December 2012 - article about the so-called Quadruple Lock which was promised to prevent religious bodies or Ministers of religion being forced into conducting same-sex marriage cerem,onies. The Spectator 5th February also considered whether the European Court of Human Rights would force churches to conduct same sex marriages. At the moment, the views of human rights lawyers have varied but it seems fair to say that the court would apply Article 9 (Freedom of thought, conscience and religion) in a way which allows the UK a wide margin of appreciation in relation to how it implements same sex marriage into national law. (A report, prepared for Parliament, considers some of the legal opinion - see para 3.3 of the report).
The Guardian 5th February - Same Sex Marriage: some inequalities remain
The Guardian 6th February - reports on the House of Commons Second Reading vote
Democracy Live 5th February - view the Second reading debate