Kenney, a devout Roman Catholic, says there is a long tradition of allowing MPs to vote their conscience on such issues in the House of Commons.
Conservative MP Stephen Woodworth's private member's motion would have a committee of MPs study the definition of a human being.
Under the Criminal Code, a child is considered a human being once it full emerges from the mother's womb at birth.
Prime Minister Stephen Harper has said he will not vote in favour of the motion because he does not wish to reopen the abortion debate.
But Woodworth says he has spoken to other cabinet ministers and is hoping for their support on Wednesday.
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