OTTAWA - Thousands of people marched through the streets of Ottawa on Thursday in an annual protest to end legalized abortions.

Throngs of teenagers, given the day off by their Roman Catholic schools to attend the event, sang "Life is Life, Na Na Na Na Na," as they drifted slowly away from Parliament Hill into the streets.

They were joined by religious leaders and people of all ages, including families with small children, in a march that lasted nearly two hours.

The protest came just two weeks after a Conservative MP tried to reopen the national abortion debate.

Prime Minister Stephen Harper rejected Stephen Woodworth's private member's motion in late April, but that didn't stop critics from accusing the Tories of using the proposal as a back-door way to rekindle debate over the sensitive topic.

While it was difficult to measure the size of the crowd on the Hill, police estimated that there were fewer people than the 15,000 that the Campaign Life Coalition claimed attended last year's event.

The protesters called on the government to legislate protection for all human beings from the time of conception to the moment of natural death.

Regardless of the prime minister's insistence that his government won't reopen the abortion debate, it's already on, said Bruce Clemenger, president of the Evangelical Fellowship of Canada.

"We cannot afford not to have the conversation," he told the crowd. "I say Parliament needs to catch up with what Canadians believe."

A few dozen pro-choice protesters were also on hand, some standing off to the side chanting "my body, my choice."

Woodworth's non-binding motion, which was debated for an hour last month, called for a special committee to study a criminal code provision that could redefine when human life begins.

It's expected to return to the House of Commons either next month or in September for another hour of debate and a vote.

CORRECTION: A previous version of this story indicated the march took place on Monday. It took place on Thursday.

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• Which Cabinet Ministers Oppose Abortion?

  The <a href="http://www.campaignlifecoalition.com/index.php?p=Find_Your_MP" target="_hplink">Campaign Life Coalition provides a listing of MPs who support and oppose abortion rights</a>. The list is based on voting records, previous comments and questionnaire responses. Here is a list of Conservative cabinet ministers who, according to the Coalition, oppose abortion. (CP)

• Rob Nicholson

  Minister of Justice and Attorney General of Canada. (CP)

• Vic Toews

  Minister of Public Safety. (CP)

• Peter Van Loan

  Leader of the Government in the House of Commons. (CP)

• Jason Kenney

  Minister of Citizenship, Immigration and Multiculturalism. (CP)

• Gerry Ritz

  Minister of Agriculture and Agri-Food Minister for the Canadian Wheat Board. (Handout)

• Ed Fast

  Minister of International Trade and Minister for the Asia-Pacific Gateway. (CP)

• Lynne Yelich

  Minister of State for Western Economic Diversification. (Handout)

• Gary Goodyear

  Minister of State for Science and Technology and for the Federal Economic Development Agency for Southern Ontario. (Handout)

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• Where The Parties Stand On Abortion

  Here's a look at the official position of Canada's federal parties, and how the controversial debate has reared its head in recent years. <em>With files from CBC</em>

• Conservative Party

  Prime Minister Stephen Harper has repeatedly said that he has no interest in addressing the issue head-on.<br><br>"As long as I am prime minister we are not opening the abortion debate," Mr. Harper said in April 2011. "The government will not bring forward any such legislation, and any such legislation that is brought forward will be defeated as long as I am prime minister." (CP)

• NDP

  NDP leader Tom Mulcair has stated that his caucus is unanimous in its opposition to the private member's motion calling on Parliament to look at whether a fetus is a human being, but he plans to force his MPs to vote along party lines.<br><br>"We're resolutely in favour of women's right to choose," Mulcair declared. (CP)

• Liberal Party

  Interim Liberal Leader Bob Rae has stressed that the abortion issue is matter of individual conscience. Rae expressed his personal opposition to reopening the debate, but said Liberal MPs will be allowed to vote "their conscience" rather than force them to toe the party line.<br><br>"Our position on reproductive choice, my position on reproductive choice is very, very clear. It has been for decades. The position is it's a person's right to choose." (CP)

• Planned Parenthood Funding Controversy

  Saskatoon-Humboldt MP Brad Trost tells Saskatchewan's ProLife Association in April 2011 that the federal government has decided to cut funding to the International Planned Parenthood Federation, a decision he says was influenced by anti-abortion supporters.<br><br>"I cannot tell you specifically how we used it, but those petitions were very, very useful and they were part of what we used to defund Planned Parenthood because it has been an absolute disgrace that that organization and several others like it have been receiving one penny of Canadian taxpayers' dollars," Trost said.<br><br>Maurice Vellacott, a Conservative MP from Saskatoon-Wanuskewin, also calls for Planned Parenthood to be defunded.<br><br>Vellacott says the controversy over the funding "exposed the lies and destructiveness of IPPF's agenda."<br><br>"It exposes what this abortion giant is surreptitiously trying to achieve worldwide."<br><br>International Cooperation Minister Bev Oda approves funding. (CP)

• 'Coerced' Abortion Law

  Conservative Winnipeg MP Rod Bruinooge proposes "Roxanne's Law" in 2010, a bill that would penalize anyone who "coerced" a woman into ending her pregnancy against her will.<br><br>"It's not just as simple as feeling pressured to get an abortion; there is a lot of discussion of sex-selection abortion these days, as well," Bruinooge told the Winnipeg Free Press. "It's part of the overall topic of intimidation that goes towards a pregnant woman."<br><br>Bruinooge insisted the bill wasn't meant to force Parliament to wade into the debate banned by Harper, stating that nothing in his bill made it illegal to abort a fetus.<br><br>But the Liberals and New Democrats saw it as a backdoor entry into the touchy topic.<br><br>"How is an abortion bill not an abortion bill?" said then-Liberal MP Anita Neville. "This certainly introduces discussion into the House of Commons and it is a rather sneaky way of doing it."<br><br>Then-NDP leader Jack Layton echoed her concerns. "You have got to wonder what is really going on here."<br><br>The bill was defeated in December of 2010, with 178 votes for and 97 against it. Harper and many Conservatives voted against it and 10 Liberals supported it. The NDP was unanimously against it. (Handout)

• Maternal Health

  International Co-operation Minister Bev Oda discloses for the first time in April 2011 that Canada will not fund abortions in its G8 child and maternal health-care initiative for developing countries.<br><br>Keith Martin, then-Liberal MP who had defected from the Tories years earlier, expressed outrage. "People here are perplexed and wondering why Canada is rolling back the clock and depriving women in developing countries from having the same rights to basic health care and access to abortion as women in Canada," he said.<br><br>Then-NDP leader Jack Layton accused the Tories of putting Canada on side with former U.S. president George Bush, who reduced support for abortion-related aid.<br><br>"It's picking up the banner that George Bush used to carry, and I think that that's not something that would be supported by the majority of Canadians, that's for sure," Layton said.<br><br>On June 25, Canada pledged $1.1 billion to a global initiative on maternal and child health for developing countries - a disproportionately high amount compared to other G8 countries. Canada did not allow for its share to be used in the funding of abortions. (CP)