OTTAWA - A backbench Tory MP is asking Parliament to study whether Canada's definition of a human being, which refers to birth, needs to be pushed back to include life in the womb.

Stephen Woodworth, a pro-life member representing a Kitchener, Ont., riding, said today he has filed a motion in the House of Commons asking for a committee to study the issue.

Woodworth, who says the issue is "relevant to the abortion issue," wants Canada to throw out its 400-year-old definition of a human being as someone who is born, saying medical evidence has shown that human beings are created sometime before birth.

Justice Minister Rob Nicholson immediately played down the move, saying the "prime minister has been very clear, our government will not reopen this debate" -- a reference to Stephen Harper's assurances that his government will not reopen the abortion question.

Woodworth's motion would have to be approved by a majority in the House of Commons before it could be considered by any special committee.

Woodworth says he wants the issue studied, and is not suggesting what the outcome might be.

"Now there might be some people who can convince themselves that a child magically transforms into a human being when their little toe pops out of the birth canal," he said in remarks for a news conference Monday.

"However, I've concluded that modern medical science will inform us that children are in reality human beings at some point before the moment of complete birth."