University of Toronto professor Jordan Peterson spoke against Bill C-16 at a Senate committee hearing Wednesday, arguing that support for the legislation was ideologically motivated.
The bill would enshrine the rights of transgender people by adding gender identity and expression to human rights and hate-crime laws.
Arguments that biology does not determine gender "stem from the humanities and are entirely ideologically driven," said Dr. Peterson, a psychology professor who has spent the past year denouncing human-rights legislation for what he sees as its potential to infringe on freedom of expression.
"It's a tenet of the ideology that identity is socially constructed. … There is no way they can win the argument but they can win the propaganda war …," he said.
The bill was passed by the House of Commons in October and is now being examined over several days of hearings by the Senate committee on legal and constitutional affairs.
A similar bill was passed by the House in 2013, but was amended and then died when the 2015 election was called.
Wednesday's hearings occurred on the same day as the International Day Against Homophobia, Transphobia and Biphobia.
About 125 protesters took to Parliament Hill to show their support for the legislation.
Dr. Peterson is a psychologist whose work has specialized in myth, religious belief and personality assessment. Since September, 2016, however, he has become a prominent figure in academic free-speech debates for his YouTube videos, campus lectures and podcast interviews where he argues against protections for gender expression in human-rights legislation.
The professor's opposition to the bill has been repeatedly cited by senators opposed to its passage. He was invited to speak as one among two dozen witnesses for the committee.
He sometimes came under intense questioning from the senators on the committee.
"Do you see a difference between the opinions you express today on this issue and the actions you take as a university professor where you are in a position of authority and power over your students?" Senator Renée Dupuis said.
"I consider myself in a position of responsibility and I don't know what that has to do with my stance," Dr. Peterson responded.