"I'm going to say something really dangerous now," warned panellist Jane Caro on Monday night's Q&A. With the special "Festival of Dangerous Ideas" episode having meandered through the pedestrian topics of toy boys, single parenthood and social media bullies, it was a welcome relief.
Asked whether prostitution could be considered a deliberate career choice, Ms Caro - an author, feminist and education expert - said that marriage, in an historical context, could itself be considered a form of the 'world's oldest profession'.
"I would argue that traditional marriage, which included conjugal rights, particularly when women were not able to go to work or were fired when they first got married, and were basically selling their bodies and their reproductive rights to their husband...was a form of prostitution," she said.
The panellists on Monday night's episode of Q&A at the Opera House.
"He bought them, by giving her room and board in return."
The comment caused a minor stir on social media, with some users calling the idea "stupid" and "immoral". A rival media outlet described it as an "odd monologue" out of touch with reality.
Fellow Q&A panellist Kajsa Ekman, a Swedish author who argued against prostitution as empowerment, said Ms Caro's comparison was "abstract".
"We're talking here about a world in which a lot of people in prostitution have sex with up to 15 buyers a day," she told the Opera House audience.
"I think that [journalist turned sex worker Amanda Goff] might soon realise it wasn't really that empowering, and that it is not representative of the majority of people who enter prostitution.
@JaneCaro My mother is a prostitute is she? Raising 4 boys makes her a whore? #qanda — Bradley Tanner (@Braddlesadl) September 2, 2014
"My definition of prostitution personally is it's sex between two people, one person that wants it and one person that doesn't. If you don't have that criteria you don't have prostitution."
Ms Caro told Fairfax Media on Tuesday that she had made a "historical analogy" rather than sought to compare modern marriage with prostitution, and did not back away from her comments.
"I talked about traditional marriage when they had conjugal rights - I didn't mention stay-at-home housewives at all," she said.
"And I'm sorry - I still think that historical analogy with the way marriage was [holds true]. I think in some parts of the world [marriage is] arguably not all that far away from prostitution."
She also joked that in times gone by "if you were a prostitute maybe it lasted an hour - if you were married it lasted a lifetime".
Ms Caro said the Q&A audience got the joke and understood the point she was making. She described her critics' subsequent response as "a beat up".
Hey, @JaneCaro. You spoke bloody good sense on #QandA last night re: marriage and prostitution. "Abstract" my arse. Please continue. — Felicity (@HorrorshowFlick) September 1, 2014
"I'm not surprised, tragically. I think it's not uncommon for people to jump on something and distort it these days, which is really sad. It was, after all, a panel about dangerous ideas."
Other feminist authors have previously made the same argument, including Sheila Jeffreys in her 2009 book The Industrial Vagina and Mary Wollstonecraft in her 1792 manifesto A Vindication of the Rights of Woman.
The issue of prostitution also caused controversy at a Festival of Dangerous Ideas event on Sunday, when three Sydney sex workers handed out flyers and posed with a sign that declared: "I am a sex worker. I am not for sale."
The demonstrators were protesting a discussion about the global sex trade in which four journalists and writers - but no actual sex workers - were invited to speak.
-with Tom Decent