The same sex marriage debate between MPs is already heating up before it begins in earnest in the House of Commons tomorrow.

On Monday, New Democrat MP Libby Davies castigated Conservative MP Jason Kenney for mentioning her same-sex relationship during his defence of traditional marriage during an interview on the weekend.

Kenney said Davies, who is openly gay, was married to a man before she entered into a relationship with her current partner. Davies said this is untrue.

"I was just outraged by what he was saying, basically invoking my relationship and my name to put out political spin for his own political purpose, which is all about dividing a community," Davies told The Globe and Mail.

Kenney, a Calgary MP, told members of the Punjabi language media in Toronto last month that gays have every right to marry whomever they want -- as long as it's someone of the opposite sex.

He noted that former NDP MP Svend Robinson -- an outspoken gay rights advocate and Canada's first publicly declared gay MP -- was once married to a woman. He also said that Davies was once married to a man.

"Marriage is open to everybody, as long as they're a man and a woman,'' said Kenney.

On CTV's Canada AM, Kenney said that he was simply quoting from "some very important judicial precedence."

He noted that the argument has been widely cited by the courts, including the Ontario Superior Court in the Halpern decision, which created the right to same sex marriage.

In June, 2003, in Halpern v. Canada (A.G.), the Ontario Court of Appeal decided to grant full and equal marriage to same-sex couples. Courts in seven provinces and one territory have found it unconstitutional to deny same-sex couples the right to marry.

"Basically, the court simply pointed out that the exclusive nature of heterosexual traditional marriage is based not on sexual orientation but on gender. And the reason for that is because only a man and a woman can transmit life," said Kenney.

He added that "most Canadians believe that a man and a woman together constitute an ideal situation for creating and raising children."

New Democrat Bill Siksay, an openly gay MP, told Canada AM that Kenney's comment "just denies the whole reality of my life."

"He doesn't recognize the fact that opposite sex marriage just isn't in the cards for me and any other gay or lesbian person in Canada. It makes us invisible in the argument and it's not acceptable," said Siksay.

He added that Kenney's "radical agenda" denies the partnerships of "people who choose not to have children or who can't have children."

Kenney said he believes marriage is not an "exclusively procreative" arrangement -- but "that's the core of it."

What the vast majority of Canadians are looking for is a "reasonable compromise," said Kenney, adding that his party supports domestic partner unions at the provincial level "which recognizes that there are non-conjugal relationships where people live in a dependent situation that deserves state recognition."

"I don't deny at all that gays and lesbians care for each other and love for each other, and indeed that should be considered in civil union relationships at the provincial level," Kenney said.

Siksay argued, however, that a "separate institution for gay and lesbian people isn't full equality and it makes us second class citizens. And that's not acceptable."

The debate on same sex marriage, which begins Wednesday in the House of Commons, is expected to be spirited -- and lengthy.

The Globe and Mail reports that the debate will probably take weeks, as the Conservatives have indicated most of their MPs want to speak on the bill.

The NDP also expects to put up several speakers, the NDP critic on the issue told the Globe.

The bill will then be sent to committee, which could also take weeks, meaning it could take until summer to clear Commons and pass before Parliament.