MacKay was responding to Wednesday's Toronto Star report about an Ontario Bar Association meeting at which he was asked about the lack of women and visible minorities on federally appointed court benches.
MacKay answered the question by saying that women don't apply to be judges because they fear the job will take them away from their children — and that children need their mothers more than their fathers, the Star report said.
On Thursday, rather than back away from the comments, MacKay stood his ground.
"At early childhood, there's no question I think that women have a greater bond with their children," he said.
Canada needs more women to apply for judicial appointments, he continued, before walking away from reporters.
Later in the House of Commons, opposition MPs pounced on MacKay's comment, declaring them sexist and demanding an apology.
"I ask the minister to apologize to all Canadians for blaming motherhood for his abject failure to ensure that the federal court reflects the diversity of society," said Liberal MP Carolyn Bennett.
MacKay insisted, however, that he was being unfairly maligned.
"That, of course, is a complete mischaracterization of what I said, what I think, how I act and who I am," he told the Commons. Judicial appointments are made solely on the basis of merit, he added.
"With respect to minorities and women being promoted to the judiciary, I think we can all agree that government, of course, plays an important role in that, but so too do law schools and law societies, and that is exactly the message I was bringing to the Ontario Bar Association."
Between 2006 and 2012, the Conservatives appointed or elevated 485 judges. Of those, 145 — 30 per cent — were women, according to the government's answer to a recent order paper question posed by Liberal MP Irwin Cotler.
MacKay updated those figures Thursday, saying the Tories have named a total of 182 justices since 2006.
As of June 1, there were 855 judges sitting on federal, provincial and territorial court benches across the country, 382 of whom were women.
Some of MacKay's Conservative colleagues appeared uncomfortable with his remarks.
Calgary MP Michelle Rempel said parliamentarians should celebrate women, no matter their career choices — including staying at home.
Ontario MP Mike Wallace, who chairs the justice committee, refused to comment on the matter, saying it's up to MacKay to defend his own statements.
And Quebec MP Maxime Bernier laughed off MacKay's comments, but was quick to point out that he has a "special bond" with his daughters.
Several men and women who were on hand for the meeting with MacKay described the minister's remarks to the Star as "disappointing," "frustrating" and "offensive."
It's not the first time MacKay has gotten himself into hot water over remarks about women.
In 2006, he was forced to apologize when he was deputy leader of the Conservative party for telling New Democrat Alexa McDonough to "stick to her knitting."
MacKay made the comment as he and McDonough appeared on a Halifax radio show where they sparred over constituency races in Nova Scotia.
Note to readers: This is a corrected story. An earlier version contained incorrect figures for the number of federal judicial appointments.
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