At the time it became law, same-sex marriage had already been legalized by court decisions in all Canadian jurisdictions except Alberta, Prince Edward Island, the Northwest Territories, and Nunavut.

Sections 2 through 4 form the substance of the Act, and were the key points of contention during its debate in the House of Commons and the Senate.

The remaining sections are "consequential amendments" that simply adjust the wording of existing acts to conform to this one.

Joe Comuzzi resigned just hours before the final vote on the Act, and Martin lamented his leaving.

C-38 was written on the basis of a draft bill produced by then-Justice minister Martin Cauchon in 2003, which had been submitted to the Supreme Court of Canada in December 2004 as the reference question Re: Same-Sex Marriage.

However, the government survived the last of the budget votes on June 23, 2005, and successfully passed a motion to extend the current sitting of Parliament.