Former prime minister Julia Gillard has sought legal advice after an anti-marriage equality group linked her apology for forced adoptions to the same-sex marriage debate.
The advertisement – which depicts same-sex marriage as harmful to children – begins with footage of Ms Gillard's 2013 apology to victims of forced adoptions.
It then warns that marriage equality would produce a "motherless generation".
The ad is understood to have been broadcast in Canberra on March 29 during WIN's telecast of movie Limitless.
The Australian Marriage Forum's advertisements have previously grabbed headlines due to a social media backlash when aired during Nine and Seven's coverage of the Sydney Gay and Lesbian Mardi Gras parade in March.
Both broadcasters later dropped the ad, while SBS refused to put it to air.
Ms Gillard and forced adoption victims slammed the forum for hijacking a historical moment to suit its divisive agenda.
But the group's president defended the ad as an "intelligent contribution to an important national debate".
A spokesman for Ms Gillard said she had been unaware of the video until The Canberra Times drew it to her attention.
The spokesman said Ms Gillard thought it wrong for her apology to be taken out of context and misused.
"As well as being hurtful to those the subject of the apology, who have already suffered so much, Ms Gillard believes the video is offensive to gay couples, who are parents," the spokesman said.
"Ms Gillard is seeking legal advice about this matter."
The videos publication coincided with the start of the Without Consent: Australia's past adoption practices exhibition at the National Archives, which catalogues the history of, and the damage caused by, past forced adoptions in Australia.
Ms Gillard was in Canberra to open the exhibition last week.
The policy saw about 250,000 newborns forcibly taken from their mothers, and given to strangers purely because of the parents unwed status.
The policy operated on the idea that the newborns would be better off with a white, married Christian couple.
Christine Cole, convenor of the Apology Alliance, which represents people affected by forced adoption, said: "It was for this policy and these dreadful past practices and the damage done to mothers fathers and adopted persons that we received a federal apology."
"It is deeply traumatising that what was for us a profoundly moving and historical moment, the apology given to us by former prime minister Julia Gillard in 2013, is used out of context and for a particular agenda."
But AMF president Dr David van Gend – who would only answer questions via email – said the footage had been used "respectfully and in the public interest".
"We were diligent to make sure the ad accurately conveys the context of Ms Gillard's quote," Dr van Gend said.
"Of course we will not remove it or stop broadcast [as] this is an intelligent contribution to an important national debate, which praises the national apology for forced adoption and Ms Gillard's words unreservedly."
Dr van Gend said the advertisement focused on how the past injustice had violated the primal bond between a mother and her baby.
"[The ad] says, 'Don't do it again! Don't violate this primal bond between mother and baby by instituting marriage without a woman, which creates families without a mother'."
"We apply the one consistent principle to two contexts, both clearly depicted."
He said he expected mothers and children affected by forced adoption would be the first to say don't do it again.
"We would expect Ms Gillard to see that her noble apology for violating that bond through forced adoption must still apply to not violating that same bond through instating marriage and adoption or surrogacy by two men."
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