Reference re Same-Sex Marriage [2004] 3 S.C.R. 698, 2004 SCC 79, was a reference question

Reference question

In Canadian law, a Reference Question is a submission by the federal or a provincial government to the courts asking for an advisory opinion on a major legal issue. Typically the question concerns the constitutionality of legislation....

 to the Supreme Court of Canada

Supreme Court of Canada

The Supreme Court of Canada is the highest court of Canada and is the final court of appeals in the Canadian justice system. The court grants permission to between 40 and 75 litigants each year to appeal decisions rendered by provincial, territorial and federal appellate courts, and its decisions...

 regarding the constitutional

Constitution of Canada

The Constitution of Canada is the supreme law in Canada; the country's constitution is an amalgamation of codified acts and uncodified traditions and conventions. It outlines Canada's system of government, as well as the civil rights of all Canadian citizens and those in Canada...

 validity of same-sex marriage in Canada

Same-sex marriage in Canada

On July 20, 2005, Canada became the fourth country in the world and the first country in the Americas to legalize same-sex marriage nationwide with the enactment of the Civil Marriage Act which provided a gender-neutral marriage definition...

. The ruling was announced December 2004, following arguments made two months prior.
Prior to this case the issue regarding the constitutional validity of same-sex marriage had been considered by several of the provinces appeal courts, all of them holding that it was constitutionally valid.