A ground-breaking ruling handed down by the Supreme Court of Canada has radically altered the way family is defined in Canada -- "spouse" now includes same-sex partners.

Read Viewpoint by Mary-Ellen Anderson: 'If I left for work one day and never came back . . .'

The Supreme Court's decision to strike down a key section of Ontario's family law on the grounds that it is unconstitutional is seen as a major victory for gays and lesbians. The Court gave Ontario six months to amend its laws, recognizing same sex couples.

McCarthy and Kyle Rae celebrate decision

Canada's top court was asked to review the definition of "spouse" in terms of whether support payments could apply to same sex couples.

The ruling centered on a case involving the breakup of two Toronto women. A woman to whom the court refers as "M" wanted her lesbian partner to pay her support after their 12-year relationship ended in 1989. Ontario family law defines a spouse as someone of the opposite sex.

McMillan Binch, the law firm which represents "M" called the 8-1 majority ruling "historic."

It could force Ontario to rewrite hundreds of laws governing family relationships. Moreover, it could force governments across Canada to rewrite laws that recognize only heterosexual relationships.

Before the ruling Toronto lawyer Martha McCarthy, who represents "M" in court documents said: "At stake is whether the doors of the family law courts should be open to gays and lesbians as they are for other unmarried couples."

The lower courts have all agreed with McCarthy's argument that drawing a distinction based on sexual orientation offends the equality guarantees of the Charter of Rights and Freedoms.

The Ontario government's argument was that the original legislation was designed to protect only those in heterosexual relationships.

Ontario is not alone in its stand. So far, only British Columbia has rewritten its laws to ensure all couples, regardless of sexual orientation, are treated the same.

Judging by statements made by the justice minister, Ottawa seems ready for a ruling that extends the rights of homosexuals. Said Anne McLellan: "Obviously, the overwhelming majority of Canadians want to ensure that people are not unfairly discriminated against."

A tide of change could begin with the court's decision.