Same-sex marriage advocates have launched a television campaign to hit back at "dishonest" ads warning gay marriage could impact what children are taught in schools.
A television ad from the Coalition for Marriage featuring three mothers warning against a "yes" vote in the upcoming postal survey has been criticised as dishonest by many Liberal and Labor politicians.
The Equality Campaign is fighting back with a commercial featuring prominent doctor Kerryn Phelps.
"Sadly, some are trying to mislead us like this ad does, by saying there will be a negative impact, including on young people," Dr Phelps says in the ad, set to hit television screens this week.
"The only young people affected by marriage equality are young gay people who for the first time will have the same dignity as everyone else in our country and they deserve that."
The three mothers in the "no" TV ad express concerns about how same-sex marriage would affect what was taught and promoted in schools.
It features Melbourne woman Cella White, who says her son was told he could wear a dress to school next year if he wanted to.
The school's principal John Albiston says her claim is false.
"She said it happened in a science class so we spoke to her son's science teachers. They said it never happened," the principal told AAP on Wednesday.
"I think it's very disappointing that she didn't meet with me to explore her concerns.
"If we had investigated it with her ... she would have realised it wasn't happening."
Education Minister Simon Birmingham said it was "patently ridiculous" to suggest marriage equality would impact what was taught in schools.
He said opponents of gay marriage were trying to conflate the simple question of whether same-sex couples should be allowed to marry with other, irrelevant, issues.
"It is trying to take the debate in a different direction which there is no validity to drag that debate to," he told ABC radio.
Liberal MP Tim Wilson also criticised the ad.
"They are creating red herrings to distract the public," he told The Project.
A voluntary postal vote on whether to legalise same-sex marriage will be held next month unless it's blocked by a looming High Court challenge.